1// -*- C++ -*-
2//===-------------------------- algorithm ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_ALGORITHM
12#define _LIBCPP_ALGORITHM
13
14/*
15    algorithm synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22template <class InputIterator, class Predicate>
23    bool
24    all_of(InputIterator first, InputIterator last, Predicate pred);
25
26template <class InputIterator, class Predicate>
27    bool
28    any_of(InputIterator first, InputIterator last, Predicate pred);
29
30template <class InputIterator, class Predicate>
31    bool
32    none_of(InputIterator first, InputIterator last, Predicate pred);
33
34template <class InputIterator, class Function>
35    Function
36    for_each(InputIterator first, InputIterator last, Function f);
37
38template <class InputIterator, class T>
39    InputIterator
40    find(InputIterator first, InputIterator last, const T& value);
41
42template <class InputIterator, class Predicate>
43    InputIterator
44    find_if(InputIterator first, InputIterator last, Predicate pred);
45
46template<class InputIterator, class Predicate>
47    InputIterator
48    find_if_not(InputIterator first, InputIterator last, Predicate pred);
49
50template <class ForwardIterator1, class ForwardIterator2>
51    ForwardIterator1
52    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
53             ForwardIterator2 first2, ForwardIterator2 last2);
54
55template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
56    ForwardIterator1
57    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
58             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
59
60template <class ForwardIterator1, class ForwardIterator2>
61    ForwardIterator1
62    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
63                  ForwardIterator2 first2, ForwardIterator2 last2);
64
65template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
66    ForwardIterator1
67    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
68                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
69
70template <class ForwardIterator>
71    ForwardIterator
72    adjacent_find(ForwardIterator first, ForwardIterator last);
73
74template <class ForwardIterator, class BinaryPredicate>
75    ForwardIterator
76    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
77
78template <class InputIterator, class T>
79    typename iterator_traits<InputIterator>::difference_type
80    count(InputIterator first, InputIterator last, const T& value);
81
82template <class InputIterator, class Predicate>
83    typename iterator_traits<InputIterator>::difference_type
84    count_if(InputIterator first, InputIterator last, Predicate pred);
85
86template <class InputIterator1, class InputIterator2>
87    pair<InputIterator1, InputIterator2>
88    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
89
90template <class InputIterator1, class InputIterator2>
91    pair<InputIterator1, InputIterator2>
92    mismatch(InputIterator1 first1, InputIterator1 last1, 
93             InputIterator2 first2, InputIterator2 last2); // **C++14**
94
95template <class InputIterator1, class InputIterator2, class BinaryPredicate>
96    pair<InputIterator1, InputIterator2>
97    mismatch(InputIterator1 first1, InputIterator1 last1,
98             InputIterator2 first2, BinaryPredicate pred);
99
100template <class InputIterator1, class InputIterator2, class BinaryPredicate>
101    pair<InputIterator1, InputIterator2>
102    mismatch(InputIterator1 first1, InputIterator1 last1,
103             InputIterator2 first2, InputIterator2 last2,
104             BinaryPredicate pred); // **C++14**
105
106template <class InputIterator1, class InputIterator2>
107    bool
108    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
109
110template <class InputIterator1, class InputIterator2>
111    bool
112    equal(InputIterator1 first1, InputIterator1 last1, 
113          InputIterator2 first2, InputIterator2 last2); // **C++14**
114
115template <class InputIterator1, class InputIterator2, class BinaryPredicate>
116    bool
117    equal(InputIterator1 first1, InputIterator1 last1,
118          InputIterator2 first2, BinaryPredicate pred);
119
120template <class InputIterator1, class InputIterator2, class BinaryPredicate>
121    bool
122    equal(InputIterator1 first1, InputIterator1 last1,
123          InputIterator2 first2, InputIterator2 last2,
124          BinaryPredicate pred); // **C++14**
125
126template<class ForwardIterator1, class ForwardIterator2>
127    bool
128    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
129                   ForwardIterator2 first2);
130
131template<class ForwardIterator1, class ForwardIterator2>
132    bool
133    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
134                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
135
136template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
137    bool
138    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
139                   ForwardIterator2 first2, BinaryPredicate pred);
140
141template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
142    bool
143    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
144                   ForwardIterator2 first2, ForwardIterator2 last2,
145                   BinaryPredicate pred);  // **C++14**
146
147template <class ForwardIterator1, class ForwardIterator2>
148    ForwardIterator1
149    search(ForwardIterator1 first1, ForwardIterator1 last1,
150           ForwardIterator2 first2, ForwardIterator2 last2);
151
152template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
153    ForwardIterator1
154    search(ForwardIterator1 first1, ForwardIterator1 last1,
155           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
156
157template <class ForwardIterator, class Size, class T>
158    ForwardIterator
159    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
160
161template <class ForwardIterator, class Size, class T, class BinaryPredicate>
162    ForwardIterator
163    search_n(ForwardIterator first, ForwardIterator last,
164             Size count, const T& value, BinaryPredicate pred);
165
166template <class InputIterator, class OutputIterator>
167    OutputIterator
168    copy(InputIterator first, InputIterator last, OutputIterator result);
169
170template<class InputIterator, class OutputIterator, class Predicate>
171    OutputIterator
172    copy_if(InputIterator first, InputIterator last,
173            OutputIterator result, Predicate pred);
174
175template<class InputIterator, class Size, class OutputIterator>
176    OutputIterator
177    copy_n(InputIterator first, Size n, OutputIterator result);
178
179template <class BidirectionalIterator1, class BidirectionalIterator2>
180    BidirectionalIterator2
181    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
182                  BidirectionalIterator2 result);
183
184template <class ForwardIterator1, class ForwardIterator2>
185    ForwardIterator2
186    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
187
188template <class ForwardIterator1, class ForwardIterator2>
189    void
190    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
191
192template <class InputIterator, class OutputIterator, class UnaryOperation>
193    OutputIterator
194    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
195
196template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
197    OutputIterator
198    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
199              OutputIterator result, BinaryOperation binary_op);
200
201template <class ForwardIterator, class T>
202    void
203    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
204
205template <class ForwardIterator, class Predicate, class T>
206    void
207    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
208
209template <class InputIterator, class OutputIterator, class T>
210    OutputIterator
211    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
212                 const T& old_value, const T& new_value);
213
214template <class InputIterator, class OutputIterator, class Predicate, class T>
215    OutputIterator
216    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
217
218template <class ForwardIterator, class T>
219    void
220    fill(ForwardIterator first, ForwardIterator last, const T& value);
221
222template <class OutputIterator, class Size, class T>
223    OutputIterator
224    fill_n(OutputIterator first, Size n, const T& value);
225
226template <class ForwardIterator, class Generator>
227    void
228    generate(ForwardIterator first, ForwardIterator last, Generator gen);
229
230template <class OutputIterator, class Size, class Generator>
231    OutputIterator
232    generate_n(OutputIterator first, Size n, Generator gen);
233
234template <class ForwardIterator, class T>
235    ForwardIterator
236    remove(ForwardIterator first, ForwardIterator last, const T& value);
237
238template <class ForwardIterator, class Predicate>
239    ForwardIterator
240    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
241
242template <class InputIterator, class OutputIterator, class T>
243    OutputIterator
244    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
245
246template <class InputIterator, class OutputIterator, class Predicate>
247    OutputIterator
248    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
249
250template <class ForwardIterator>
251    ForwardIterator
252    unique(ForwardIterator first, ForwardIterator last);
253
254template <class ForwardIterator, class BinaryPredicate>
255    ForwardIterator
256    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
257
258template <class InputIterator, class OutputIterator>
259    OutputIterator
260    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
261
262template <class InputIterator, class OutputIterator, class BinaryPredicate>
263    OutputIterator
264    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
265
266template <class BidirectionalIterator>
267    void
268    reverse(BidirectionalIterator first, BidirectionalIterator last);
269
270template <class BidirectionalIterator, class OutputIterator>
271    OutputIterator
272    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
273
274template <class ForwardIterator>
275    ForwardIterator
276    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
277
278template <class ForwardIterator, class OutputIterator>
279    OutputIterator
280    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
281
282template <class RandomAccessIterator>
283    void
284    random_shuffle(RandomAccessIterator first, RandomAccessIterator last); // deprecated in C++14
285
286template <class RandomAccessIterator, class RandomNumberGenerator>
287    void
288    random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
289                   RandomNumberGenerator& rand);  // deprecated in C++14
290
291template<class RandomAccessIterator, class UniformRandomNumberGenerator>
292    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
293                 UniformRandomNumberGenerator&& g);
294
295template <class InputIterator, class Predicate>
296    bool
297    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
298
299template <class ForwardIterator, class Predicate>
300    ForwardIterator
301    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
302
303template <class InputIterator, class OutputIterator1,
304          class OutputIterator2, class Predicate>
305    pair<OutputIterator1, OutputIterator2>
306    partition_copy(InputIterator first, InputIterator last,
307                   OutputIterator1 out_true, OutputIterator2 out_false,
308                   Predicate pred);
309
310template <class ForwardIterator, class Predicate>
311    ForwardIterator
312    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
313
314template<class ForwardIterator, class Predicate>
315    ForwardIterator
316    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
317
318template <class ForwardIterator>
319    bool
320    is_sorted(ForwardIterator first, ForwardIterator last);
321
322template <class ForwardIterator, class Compare>
323    bool
324    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
325
326template<class ForwardIterator>
327    ForwardIterator
328    is_sorted_until(ForwardIterator first, ForwardIterator last);
329
330template <class ForwardIterator, class Compare>
331    ForwardIterator
332    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
333
334template <class RandomAccessIterator>
335    void
336    sort(RandomAccessIterator first, RandomAccessIterator last);
337
338template <class RandomAccessIterator, class Compare>
339    void
340    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
341
342template <class RandomAccessIterator>
343    void
344    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
345
346template <class RandomAccessIterator, class Compare>
347    void
348    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
349
350template <class RandomAccessIterator>
351    void
352    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
353
354template <class RandomAccessIterator, class Compare>
355    void
356    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
357
358template <class InputIterator, class RandomAccessIterator>
359    RandomAccessIterator
360    partial_sort_copy(InputIterator first, InputIterator last,
361                      RandomAccessIterator result_first, RandomAccessIterator result_last);
362
363template <class InputIterator, class RandomAccessIterator, class Compare>
364    RandomAccessIterator
365    partial_sort_copy(InputIterator first, InputIterator last,
366                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
367
368template <class RandomAccessIterator>
369    void
370    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
371
372template <class RandomAccessIterator, class Compare>
373    void
374    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
375
376template <class ForwardIterator, class T>
377    ForwardIterator
378    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
379
380template <class ForwardIterator, class T, class Compare>
381    ForwardIterator
382    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
383
384template <class ForwardIterator, class T>
385    ForwardIterator
386    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
387
388template <class ForwardIterator, class T, class Compare>
389    ForwardIterator
390    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
391
392template <class ForwardIterator, class T>
393    pair<ForwardIterator, ForwardIterator>
394    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
395
396template <class ForwardIterator, class T, class Compare>
397    pair<ForwardIterator, ForwardIterator>
398    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
399
400template <class ForwardIterator, class T>
401    bool
402    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
403
404template <class ForwardIterator, class T, class Compare>
405    bool
406    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
407
408template <class InputIterator1, class InputIterator2, class OutputIterator>
409    OutputIterator
410    merge(InputIterator1 first1, InputIterator1 last1,
411          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
412
413template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
414    OutputIterator
415    merge(InputIterator1 first1, InputIterator1 last1,
416          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
417
418template <class BidirectionalIterator>
419    void
420    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
421
422template <class BidirectionalIterator, class Compare>
423    void
424    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
425
426template <class InputIterator1, class InputIterator2>
427    bool
428    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
429
430template <class InputIterator1, class InputIterator2, class Compare>
431    bool
432    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
433
434template <class InputIterator1, class InputIterator2, class OutputIterator>
435    OutputIterator
436    set_union(InputIterator1 first1, InputIterator1 last1,
437              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
438
439template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
440    OutputIterator
441    set_union(InputIterator1 first1, InputIterator1 last1,
442              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
443
444template <class InputIterator1, class InputIterator2, class OutputIterator>
445    OutputIterator
446    set_intersection(InputIterator1 first1, InputIterator1 last1,
447                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
448
449template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
450    OutputIterator
451    set_intersection(InputIterator1 first1, InputIterator1 last1,
452                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
453
454template <class InputIterator1, class InputIterator2, class OutputIterator>
455    OutputIterator
456    set_difference(InputIterator1 first1, InputIterator1 last1,
457                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
458
459template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
460    OutputIterator
461    set_difference(InputIterator1 first1, InputIterator1 last1,
462                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
463
464template <class InputIterator1, class InputIterator2, class OutputIterator>
465    OutputIterator
466    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
467                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
468
469template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
470    OutputIterator
471    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
472                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
473
474template <class RandomAccessIterator>
475    void
476    push_heap(RandomAccessIterator first, RandomAccessIterator last);
477
478template <class RandomAccessIterator, class Compare>
479    void
480    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
481
482template <class RandomAccessIterator>
483    void
484    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
485
486template <class RandomAccessIterator, class Compare>
487    void
488    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
489
490template <class RandomAccessIterator>
491    void
492    make_heap(RandomAccessIterator first, RandomAccessIterator last);
493
494template <class RandomAccessIterator, class Compare>
495    void
496    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
497
498template <class RandomAccessIterator>
499    void
500    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
501
502template <class RandomAccessIterator, class Compare>
503    void
504    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
505
506template <class RandomAccessIterator>
507    bool
508    is_heap(RandomAccessIterator first, RandomAccessiterator last);
509
510template <class RandomAccessIterator, class Compare>
511    bool
512    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
513
514template <class RandomAccessIterator>
515    RandomAccessIterator
516    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
517
518template <class RandomAccessIterator, class Compare>
519    RandomAccessIterator
520    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
521
522template <class ForwardIterator>
523    ForwardIterator
524    min_element(ForwardIterator first, ForwardIterator last);
525
526template <class ForwardIterator, class Compare>
527    ForwardIterator
528    min_element(ForwardIterator first, ForwardIterator last, Compare comp);
529
530template <class T>
531    const T&
532    min(const T& a, const T& b);  // constexpr in C++14
533
534template <class T, class Compare>
535    const T&
536    min(const T& a, const T& b, Compare comp);  // constexpr in C++14
537
538template<class T>
539    T
540    min(initializer_list<T> t);  // constexpr in C++14
541
542template<class T, class Compare>
543    T
544    min(initializer_list<T> t, Compare comp);  // constexpr in C++14
545
546template <class ForwardIterator>
547    ForwardIterator
548    max_element(ForwardIterator first, ForwardIterator last);
549
550template <class ForwardIterator, class Compare>
551    ForwardIterator
552    max_element(ForwardIterator first, ForwardIterator last, Compare comp);
553
554template <class T>
555    const T&
556    max(const T& a, const T& b); // constexpr in C++14
557
558template <class T, class Compare>
559    const T&
560    max(const T& a, const T& b, Compare comp);  // constexpr in C++14
561
562template<class T>
563    T
564    max(initializer_list<T> t);  // constexpr in C++14
565
566template<class T, class Compare>
567    T
568    max(initializer_list<T> t, Compare comp);  // constexpr in C++14
569
570template<class ForwardIterator>
571    pair<ForwardIterator, ForwardIterator>
572    minmax_element(ForwardIterator first, ForwardIterator last);
573
574template<class ForwardIterator, class Compare>
575    pair<ForwardIterator, ForwardIterator>
576    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);
577
578template<class T>
579    pair<const T&, const T&>
580    minmax(const T& a, const T& b);  // constexpr in C++14
581
582template<class T, class Compare>
583    pair<const T&, const T&>
584    minmax(const T& a, const T& b, Compare comp);  // constexpr in C++14
585
586template<class T>
587    pair<T, T>
588    minmax(initializer_list<T> t);  // constexpr in C++14
589
590template<class T, class Compare>
591    pair<T, T>
592    minmax(initializer_list<T> t, Compare comp);  // constexpr in C++14
593
594template <class InputIterator1, class InputIterator2>
595    bool
596    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
597
598template <class InputIterator1, class InputIterator2, class Compare>
599    bool
600    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
601                            InputIterator2 first2, InputIterator2 last2, Compare comp);
602
603template <class BidirectionalIterator>
604    bool
605    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
606
607template <class BidirectionalIterator, class Compare>
608    bool
609    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
610
611template <class BidirectionalIterator>
612    bool
613    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
614
615template <class BidirectionalIterator, class Compare>
616    bool
617    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
618
619}  // std
620
621*/
622
623#include <__config>
624#include <initializer_list>
625#include <type_traits>
626#include <cstring>
627#include <utility>
628#include <memory>
629#include <iterator>
630#include <cstddef>
631
632#if defined(__IBMCPP__)
633#include "support/ibm/support.h"
634#endif
635#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
636#include "support/win32/support.h"
637#endif
638
639#include <__undef_min_max>
640
641#include <__debug>
642
643#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
644#pragma GCC system_header
645#endif
646
647_LIBCPP_BEGIN_NAMESPACE_STD
648
649// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
650//   * That only works with C++14 and later, and
651//   * We haven't included <functional> here.
652template <class _T1, class _T2 = _T1>
653struct __equal_to
654{
655    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
656    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
657    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
658    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
659};
660
661template <class _T1>
662struct __equal_to<_T1, _T1>
663{
664    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
665    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
666};
667
668template <class _T1>
669struct __equal_to<const _T1, _T1>
670{
671    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
672    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
673};
674
675template <class _T1>
676struct __equal_to<_T1, const _T1>
677{
678    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
679    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
680};
681
682template <class _T1, class _T2 = _T1>
683struct __less
684{
685    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 
686    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
687
688    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
689    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
690
691    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
692    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
693
694    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
695    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
696};
697
698template <class _T1>
699struct __less<_T1, _T1>
700{
701    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
702    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
703};
704
705template <class _T1>
706struct __less<const _T1, _T1>
707{
708    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
709    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
710};
711
712template <class _T1>
713struct __less<_T1, const _T1>
714{
715    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
716    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
717};
718
719template <class _Predicate>
720class __negate
721{
722private:
723    _Predicate __p_;
724public:
725    _LIBCPP_INLINE_VISIBILITY __negate() {}
726
727    _LIBCPP_INLINE_VISIBILITY
728    explicit __negate(_Predicate __p) : __p_(__p) {}
729
730    template <class _T1>
731    _LIBCPP_INLINE_VISIBILITY
732    bool operator()(const _T1& __x) {return !__p_(__x);}
733
734    template <class _T1, class _T2>
735    _LIBCPP_INLINE_VISIBILITY
736    bool operator()(const _T1& __x, const _T2& __y) {return !__p_(__x, __y);}
737};
738
739#ifdef _LIBCPP_DEBUG
740
741template <class _Compare>
742struct __debug_less
743{
744    _Compare __comp_;
745    __debug_less(_Compare& __c) : __comp_(__c) {}
746    template <class _Tp, class _Up>
747    bool operator()(const _Tp& __x, const _Up& __y)
748    {
749        bool __r = __comp_(__x, __y);
750        if (__r)
751            _LIBCPP_ASSERT(!__comp_(__y, __x), "Comparator does not induce a strict weak ordering");
752        return __r;
753    }
754};
755
756#endif  // _LIBCPP_DEBUG
757
758// Precondition:  __x != 0
759inline _LIBCPP_INLINE_VISIBILITY
760unsigned
761__ctz(unsigned __x)
762{
763    return static_cast<unsigned>(__builtin_ctz(__x));
764}
765
766inline _LIBCPP_INLINE_VISIBILITY
767unsigned long
768__ctz(unsigned long __x)
769{
770    return static_cast<unsigned long>(__builtin_ctzl(__x));
771}
772
773inline _LIBCPP_INLINE_VISIBILITY
774unsigned long long
775__ctz(unsigned long long __x)
776{
777    return static_cast<unsigned long long>(__builtin_ctzll(__x));
778}
779
780// Precondition:  __x != 0
781inline _LIBCPP_INLINE_VISIBILITY
782unsigned
783__clz(unsigned __x)
784{
785    return static_cast<unsigned>(__builtin_clz(__x));
786}
787
788inline _LIBCPP_INLINE_VISIBILITY
789unsigned long
790__clz(unsigned long __x)
791{
792    return static_cast<unsigned long>(__builtin_clzl (__x));
793}
794
795inline _LIBCPP_INLINE_VISIBILITY
796unsigned long long
797__clz(unsigned long long __x)
798{
799    return static_cast<unsigned long long>(__builtin_clzll(__x));
800}
801
802inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned           __x) {return __builtin_popcount  (__x);}
803inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned      long __x) {return __builtin_popcountl (__x);}
804inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {return __builtin_popcountll(__x);}
805
806// all_of
807
808template <class _InputIterator, class _Predicate>
809inline _LIBCPP_INLINE_VISIBILITY
810bool
811all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
812{
813    for (; __first != __last; ++__first)
814        if (!__pred(*__first))
815            return false;
816    return true;
817}
818
819// any_of
820
821template <class _InputIterator, class _Predicate>
822inline _LIBCPP_INLINE_VISIBILITY
823bool
824any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
825{
826    for (; __first != __last; ++__first)
827        if (__pred(*__first))
828            return true;
829    return false;
830}
831
832// none_of
833
834template <class _InputIterator, class _Predicate>
835inline _LIBCPP_INLINE_VISIBILITY
836bool
837none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
838{
839    for (; __first != __last; ++__first)
840        if (__pred(*__first))
841            return false;
842    return true;
843}
844
845// for_each
846
847template <class _InputIterator, class _Function>
848inline _LIBCPP_INLINE_VISIBILITY
849_Function
850for_each(_InputIterator __first, _InputIterator __last, _Function __f)
851{
852    for (; __first != __last; ++__first)
853        __f(*__first);
854    return _VSTD::move(__f);  // explicitly moved for (emulated) C++03
855}
856
857// find
858
859template <class _InputIterator, class _Tp>
860inline _LIBCPP_INLINE_VISIBILITY
861_InputIterator
862find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
863{
864    for (; __first != __last; ++__first)
865        if (*__first == __value_)
866            break;
867    return __first;
868}
869
870// find_if
871
872template <class _InputIterator, class _Predicate>
873inline _LIBCPP_INLINE_VISIBILITY
874_InputIterator
875find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
876{
877    for (; __first != __last; ++__first)
878        if (__pred(*__first))
879            break;
880    return __first;
881}
882
883// find_if_not
884
885template<class _InputIterator, class _Predicate>
886inline _LIBCPP_INLINE_VISIBILITY
887_InputIterator
888find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
889{
890    for (; __first != __last; ++__first)
891        if (!__pred(*__first))
892            break;
893    return __first;
894}
895
896// find_end
897
898template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
899_ForwardIterator1
900__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
901           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
902           forward_iterator_tag, forward_iterator_tag)
903{
904    // modeled after search algorithm
905    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
906    if (__first2 == __last2)
907        return __r;
908    while (true)
909    {
910        while (true)
911        {
912            if (__first1 == __last1)         // if source exhausted return last correct answer
913                return __r;                  //    (or __last1 if never found)
914            if (__pred(*__first1, *__first2))
915                break;
916            ++__first1;
917        }
918        // *__first1 matches *__first2, now match elements after here
919        _ForwardIterator1 __m1 = __first1;
920        _ForwardIterator2 __m2 = __first2;
921        while (true)
922        {
923            if (++__m2 == __last2)
924            {                         // Pattern exhaused, record answer and search for another one
925                __r = __first1;
926                ++__first1;
927                break;
928            }
929            if (++__m1 == __last1)     // Source exhausted, return last answer
930                return __r;
931            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
932            {
933                ++__first1;
934                break;
935            }  // else there is a match, check next elements
936        }
937    }
938}
939
940template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
941_BidirectionalIterator1
942__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
943           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
944           bidirectional_iterator_tag, bidirectional_iterator_tag)
945{
946    // modeled after search algorithm (in reverse)
947    if (__first2 == __last2)
948        return __last1;  // Everything matches an empty sequence
949    _BidirectionalIterator1 __l1 = __last1;
950    _BidirectionalIterator2 __l2 = __last2;
951    --__l2;
952    while (true)
953    {
954        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
955        while (true)
956        {
957            if (__first1 == __l1)  // return __last1 if no element matches *__first2
958                return __last1;
959            if (__pred(*--__l1, *__l2))
960                break;
961        }
962        // *__l1 matches *__l2, now match elements before here
963        _BidirectionalIterator1 __m1 = __l1;
964        _BidirectionalIterator2 __m2 = __l2;
965        while (true)
966        {
967            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
968                return __m1;
969            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
970                return __last1;
971            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
972            {
973                break;
974            }  // else there is a match, check next elements
975        }
976    }
977}
978
979template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
980_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
981__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
982           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
983           random_access_iterator_tag, random_access_iterator_tag)
984{
985    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
986    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
987    if (__len2 == 0)
988        return __last1;
989    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
990    if (__len1 < __len2)
991        return __last1;
992    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
993    _RandomAccessIterator1 __l1 = __last1;
994    _RandomAccessIterator2 __l2 = __last2;
995    --__l2;
996    while (true)
997    {
998        while (true)
999        {
1000            if (__s == __l1)
1001                return __last1;
1002            if (__pred(*--__l1, *__l2))
1003                break;
1004        }
1005        _RandomAccessIterator1 __m1 = __l1;
1006        _RandomAccessIterator2 __m2 = __l2;
1007        while (true)
1008        {
1009            if (__m2 == __first2)
1010                return __m1;
1011                                 // no need to check range on __m1 because __s guarantees we have enough source
1012            if (!__pred(*--__m1, *--__m2))
1013            {
1014                break;
1015            }
1016        }
1017    }
1018}
1019
1020template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1021inline _LIBCPP_INLINE_VISIBILITY
1022_ForwardIterator1
1023find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1024         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1025{
1026    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
1027                         (__first1, __last1, __first2, __last2, __pred,
1028                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1029                          typename iterator_traits<_ForwardIterator2>::iterator_category());
1030}
1031
1032template <class _ForwardIterator1, class _ForwardIterator2>
1033inline _LIBCPP_INLINE_VISIBILITY
1034_ForwardIterator1
1035find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1036         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1037{
1038    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1039    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1040    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1041}
1042
1043// find_first_of
1044
1045template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1046_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1
1047__find_first_of_ce(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1048              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1049{
1050    for (; __first1 != __last1; ++__first1)
1051        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1052            if (__pred(*__first1, *__j))
1053                return __first1;
1054    return __last1;
1055}
1056
1057
1058template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1059inline _LIBCPP_INLINE_VISIBILITY
1060_ForwardIterator1
1061find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1062              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1063{
1064    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
1065}
1066
1067template <class _ForwardIterator1, class _ForwardIterator2>
1068inline _LIBCPP_INLINE_VISIBILITY
1069_ForwardIterator1
1070find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1071              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1072{
1073    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1074    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1075    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1076}
1077
1078// adjacent_find
1079
1080template <class _ForwardIterator, class _BinaryPredicate>
1081inline _LIBCPP_INLINE_VISIBILITY
1082_ForwardIterator
1083adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
1084{
1085    if (__first != __last)
1086    {
1087        _ForwardIterator __i = __first;
1088        while (++__i != __last)
1089        {
1090            if (__pred(*__first, *__i))
1091                return __first;
1092            __first = __i;
1093        }
1094    }
1095    return __last;
1096}
1097
1098template <class _ForwardIterator>
1099inline _LIBCPP_INLINE_VISIBILITY
1100_ForwardIterator
1101adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
1102{
1103    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1104    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
1105}
1106
1107// count
1108
1109template <class _InputIterator, class _Tp>
1110inline _LIBCPP_INLINE_VISIBILITY
1111typename iterator_traits<_InputIterator>::difference_type
1112count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
1113{
1114    typename iterator_traits<_InputIterator>::difference_type __r(0);
1115    for (; __first != __last; ++__first)
1116        if (*__first == __value_)
1117            ++__r;
1118    return __r;
1119}
1120
1121// count_if
1122
1123template <class _InputIterator, class _Predicate>
1124inline _LIBCPP_INLINE_VISIBILITY
1125typename iterator_traits<_InputIterator>::difference_type
1126count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1127{
1128    typename iterator_traits<_InputIterator>::difference_type __r(0);
1129    for (; __first != __last; ++__first)
1130        if (__pred(*__first))
1131            ++__r;
1132    return __r;
1133}
1134
1135// mismatch
1136
1137template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1138inline _LIBCPP_INLINE_VISIBILITY
1139pair<_InputIterator1, _InputIterator2>
1140mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1141         _InputIterator2 __first2, _BinaryPredicate __pred)
1142{
1143    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1144        if (!__pred(*__first1, *__first2))
1145            break;
1146    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1147}
1148
1149template <class _InputIterator1, class _InputIterator2>
1150inline _LIBCPP_INLINE_VISIBILITY
1151pair<_InputIterator1, _InputIterator2>
1152mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1153{
1154    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1155    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1156    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1157}
1158
1159#if _LIBCPP_STD_VER > 11
1160template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1161inline _LIBCPP_INLINE_VISIBILITY
1162pair<_InputIterator1, _InputIterator2>
1163mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1164         _InputIterator2 __first2, _InputIterator2 __last2,
1165         _BinaryPredicate __pred)
1166{
1167    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1168        if (!__pred(*__first1, *__first2))
1169            break;
1170    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1171}
1172
1173template <class _InputIterator1, class _InputIterator2>
1174inline _LIBCPP_INLINE_VISIBILITY
1175pair<_InputIterator1, _InputIterator2>
1176mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1177         _InputIterator2 __first2, _InputIterator2 __last2)
1178{
1179    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1180    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1181    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1182}
1183#endif
1184
1185// equal
1186
1187template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1188inline _LIBCPP_INLINE_VISIBILITY
1189bool
1190equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
1191{
1192    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1193        if (!__pred(*__first1, *__first2))
1194            return false;
1195    return true;
1196}
1197
1198template <class _InputIterator1, class _InputIterator2>
1199inline _LIBCPP_INLINE_VISIBILITY
1200bool
1201equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1202{
1203    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1204    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1205    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1206}
1207
1208#if _LIBCPP_STD_VER > 11
1209template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
1210inline _LIBCPP_INLINE_VISIBILITY
1211bool
1212__equal(_InputIterator1 __first1, _InputIterator1 __last1, 
1213        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
1214        input_iterator_tag, input_iterator_tag )
1215{
1216    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1217        if (!__pred(*__first1, *__first2))
1218            return false;
1219    return __first1 == __last1 && __first2 == __last2;
1220}
1221
1222template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1223inline _LIBCPP_INLINE_VISIBILITY
1224bool
1225__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, 
1226        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred, 
1227      random_access_iterator_tag, random_access_iterator_tag )
1228{
1229    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1230        return false;
1231    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
1232                        typename add_lvalue_reference<_BinaryPredicate>::type>
1233                       (__first1, __last1, __first2, __pred );
1234}
1235
1236template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1237inline _LIBCPP_INLINE_VISIBILITY
1238bool
1239equal(_InputIterator1 __first1, _InputIterator1 __last1, 
1240      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
1241{
1242    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
1243       (__first1, __last1, __first2, __last2, __pred, 
1244        typename iterator_traits<_InputIterator1>::iterator_category(),
1245        typename iterator_traits<_InputIterator2>::iterator_category());
1246}
1247
1248template <class _InputIterator1, class _InputIterator2>
1249inline _LIBCPP_INLINE_VISIBILITY
1250bool
1251equal(_InputIterator1 __first1, _InputIterator1 __last1, 
1252      _InputIterator2 __first2, _InputIterator2 __last2)
1253{
1254    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1255    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1256    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
1257        typename iterator_traits<_InputIterator1>::iterator_category(),
1258        typename iterator_traits<_InputIterator2>::iterator_category());
1259}
1260#endif
1261
1262// is_permutation
1263
1264template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1265bool
1266is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1267               _ForwardIterator2 __first2, _BinaryPredicate __pred)
1268{
1269    // shorten sequences as much as possible by lopping of any equal parts
1270    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1271        if (!__pred(*__first1, *__first2))
1272            goto __not_done;
1273    return true;
1274__not_done:
1275    // __first1 != __last1 && *__first1 != *__first2
1276    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1277    _D1 __l1 = _VSTD::distance(__first1, __last1);
1278    if (__l1 == _D1(1))
1279        return false;
1280    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
1281    // For each element in [f1, l1) see if there are the same number of
1282    //    equal elements in [f2, l2)
1283    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1284    {
1285        // Have we already counted the number of *__i in [f1, l1)?
1286        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1287            if (__pred(*__j, *__i))
1288                goto __next_iter;
1289        {
1290            // Count number of *__i in [f2, l2)
1291            _D1 __c2 = 0;
1292            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1293                if (__pred(*__i, *__j))
1294                    ++__c2;
1295            if (__c2 == 0)
1296                return false;
1297            // Count number of *__i in [__i, l1) (we can start with 1)
1298            _D1 __c1 = 1;
1299            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1300                if (__pred(*__i, *__j))
1301                    ++__c1;
1302            if (__c1 != __c2)
1303                return false;
1304        }
1305__next_iter:;
1306    }
1307    return true;
1308}
1309
1310template<class _ForwardIterator1, class _ForwardIterator2>
1311inline _LIBCPP_INLINE_VISIBILITY
1312bool
1313is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1314               _ForwardIterator2 __first2)
1315{
1316    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1317    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1318    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1319}
1320
1321#if _LIBCPP_STD_VER > 11
1322template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1323bool
1324__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1325                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, 
1326                 _BinaryPredicate __pred,
1327                 forward_iterator_tag, forward_iterator_tag )
1328{
1329    // shorten sequences as much as possible by lopping of any equal parts
1330    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1331        if (!__pred(*__first1, *__first2))
1332            goto __not_done;
1333    return __first1 == __last1 && __first2 == __last2;
1334__not_done:
1335    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
1336    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1337    _D1 __l1 = _VSTD::distance(__first1, __last1);
1338
1339    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
1340    _D2 __l2 = _VSTD::distance(__first2, __last2);
1341    if (__l1 != __l2)
1342        return false;
1343
1344    // For each element in [f1, l1) see if there are the same number of
1345    //    equal elements in [f2, l2)
1346    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1347    {
1348        // Have we already counted the number of *__i in [f1, l1)?
1349        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1350            if (__pred(*__j, *__i))
1351                goto __next_iter;
1352        {
1353            // Count number of *__i in [f2, l2)
1354            _D1 __c2 = 0;
1355            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1356                if (__pred(*__i, *__j))
1357                    ++__c2;
1358            if (__c2 == 0)
1359                return false;
1360            // Count number of *__i in [__i, l1) (we can start with 1)
1361            _D1 __c1 = 1;
1362            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1363                if (__pred(*__i, *__j))
1364                    ++__c1;
1365            if (__c1 != __c2)
1366                return false;
1367        }
1368__next_iter:;
1369    }
1370    return true;
1371}
1372
1373template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1374bool
1375__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
1376               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2, 
1377               _BinaryPredicate __pred,
1378               random_access_iterator_tag, random_access_iterator_tag )
1379{
1380    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1381        return false;
1382    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
1383                                 typename add_lvalue_reference<_BinaryPredicate>::type>
1384                                (__first1, __last1, __first2, __pred );
1385}
1386
1387template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1388inline _LIBCPP_INLINE_VISIBILITY
1389bool
1390is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1391               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1392               _BinaryPredicate __pred )
1393{
1394    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
1395       (__first1, __last1, __first2, __last2, __pred,
1396        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1397        typename iterator_traits<_ForwardIterator2>::iterator_category());
1398}
1399
1400template<class _ForwardIterator1, class _ForwardIterator2>
1401inline _LIBCPP_INLINE_VISIBILITY
1402bool
1403is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1404               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1405{
1406    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1407    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1408    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
1409        __equal_to<__v1, __v2>(),
1410        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1411        typename iterator_traits<_ForwardIterator2>::iterator_category());
1412}
1413#endif
1414
1415// search
1416
1417template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1418_ForwardIterator1
1419__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1420         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1421         forward_iterator_tag, forward_iterator_tag)
1422{
1423    if (__first2 == __last2)
1424        return __first1;  // Everything matches an empty sequence
1425    while (true)
1426    {
1427        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
1428        while (true)
1429        {
1430            if (__first1 == __last1)  // return __last1 if no element matches *__first2
1431                return __last1;
1432            if (__pred(*__first1, *__first2))
1433                break;
1434            ++__first1;
1435        }
1436        // *__first1 matches *__first2, now match elements after here
1437        _ForwardIterator1 __m1 = __first1;
1438        _ForwardIterator2 __m2 = __first2;
1439        while (true)
1440        {
1441            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
1442                return __first1;
1443            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
1444                return __last1;
1445            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
1446            {
1447                ++__first1;
1448                break;
1449            }  // else there is a match, check next elements
1450        }
1451    }
1452}
1453
1454template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1455_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
1456__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1457           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1458           random_access_iterator_tag, random_access_iterator_tag)
1459{
1460    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _D1;
1461    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _D2;
1462    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1463    _D2 __len2 = __last2 - __first2;
1464    if (__len2 == 0)
1465        return __first1;
1466    _D1 __len1 = __last1 - __first1;
1467    if (__len1 < __len2)
1468        return __last1;
1469    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
1470    while (true)
1471    {
1472#if !_LIBCPP_UNROLL_LOOPS
1473        while (true)
1474        {
1475            if (__first1 == __s)
1476                return __last1;
1477            if (__pred(*__first1, *__first2))
1478                break;
1479            ++__first1;
1480        }
1481#else  // !_LIBCPP_UNROLL_LOOPS
1482        for (_D1 __loop_unroll = (__s - __first1) / 4; __loop_unroll > 0; --__loop_unroll)
1483        {
1484            if (__pred(*__first1, *__first2))
1485                goto __phase2;
1486            if (__pred(*++__first1, *__first2))
1487                goto __phase2;
1488            if (__pred(*++__first1, *__first2))
1489                goto __phase2;
1490            if (__pred(*++__first1, *__first2))
1491                goto __phase2;
1492            ++__first1;
1493        }
1494        switch (__s - __first1)
1495        {
1496        case 3:
1497            if (__pred(*__first1, *__first2))
1498                break;
1499            ++__first1;
1500        case 2:
1501            if (__pred(*__first1, *__first2))
1502                break;
1503            ++__first1;
1504        case 1:
1505            if (__pred(*__first1, *__first2))
1506                break;
1507        case 0:
1508            return __last1;
1509        }
1510    __phase2:
1511#endif  // !_LIBCPP_UNROLL_LOOPS
1512        _RandomAccessIterator1 __m1 = __first1;
1513        _RandomAccessIterator2 __m2 = __first2;
1514#if !_LIBCPP_UNROLL_LOOPS
1515         while (true)
1516         {
1517             if (++__m2 == __last2)
1518                 return __first1;
1519             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
1520             if (!__pred(*__m1, *__m2))
1521             {
1522                 ++__first1;
1523                 break;
1524             }
1525         }
1526#else  // !_LIBCPP_UNROLL_LOOPS
1527        ++__m2;
1528        ++__m1;
1529        for (_D2 __loop_unroll = (__last2 - __m2) / 4; __loop_unroll > 0; --__loop_unroll)
1530        {
1531            if (!__pred(*__m1, *__m2))
1532                goto __continue;
1533            if (!__pred(*++__m1, *++__m2))
1534                goto __continue;
1535            if (!__pred(*++__m1, *++__m2))
1536                goto __continue;
1537            if (!__pred(*++__m1, *++__m2))
1538                goto __continue;
1539            ++__m1;
1540            ++__m2;
1541        }
1542        switch (__last2 - __m2)
1543        {
1544        case 3:
1545            if (!__pred(*__m1, *__m2))
1546                break;
1547            ++__m1;
1548            ++__m2;
1549        case 2:
1550            if (!__pred(*__m1, *__m2))
1551                break;
1552            ++__m1;
1553            ++__m2;
1554        case 1:
1555            if (!__pred(*__m1, *__m2))
1556                break;
1557        case 0:
1558            return __first1;
1559        }
1560    __continue:
1561        ++__first1;
1562#endif  // !_LIBCPP_UNROLL_LOOPS
1563    }
1564}
1565
1566template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1567inline _LIBCPP_INLINE_VISIBILITY
1568_ForwardIterator1
1569search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1570       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1571{
1572    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
1573                         (__first1, __last1, __first2, __last2, __pred,
1574                          typename std::iterator_traits<_ForwardIterator1>::iterator_category(),
1575                          typename std::iterator_traits<_ForwardIterator2>::iterator_category());
1576}
1577
1578template <class _ForwardIterator1, class _ForwardIterator2>
1579inline _LIBCPP_INLINE_VISIBILITY
1580_ForwardIterator1
1581search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1582       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1583{
1584    typedef typename std::iterator_traits<_ForwardIterator1>::value_type __v1;
1585    typedef typename std::iterator_traits<_ForwardIterator2>::value_type __v2;
1586    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1587}
1588
1589// search_n
1590
1591template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
1592_ForwardIterator
1593__search_n(_ForwardIterator __first, _ForwardIterator __last,
1594           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
1595{
1596    if (__count <= 0)
1597        return __first;
1598    while (true)
1599    {
1600        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1601        while (true)
1602        {
1603            if (__first == __last)  // return __last if no element matches __value_
1604                return __last;
1605            if (__pred(*__first, __value_))
1606                break;
1607            ++__first;
1608        }
1609        // *__first matches __value_, now match elements after here
1610        _ForwardIterator __m = __first;
1611        _Size __c(0);
1612        while (true)
1613        {
1614            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1615                return __first;
1616            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
1617                return __last;
1618            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1619            {
1620                __first = __m;
1621                ++__first;
1622                break;
1623            }  // else there is a match, check next elements
1624        }
1625    }
1626}
1627
1628template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
1629_RandomAccessIterator
1630__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
1631           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
1632{
1633    if (__count <= 0)
1634        return __first;
1635    _Size __len = static_cast<_Size>(__last - __first);
1636    if (__len < __count)
1637        return __last;
1638    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
1639    while (true)
1640    {
1641        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1642        while (true)
1643        {
1644            if (__first >= __s)  // return __last if no element matches __value_
1645                return __last;
1646            if (__pred(*__first, __value_))
1647                break;
1648            ++__first;
1649        }
1650        // *__first matches __value_, now match elements after here
1651        _RandomAccessIterator __m = __first;
1652        _Size __c(0);
1653        while (true)
1654        {
1655            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1656                return __first;
1657             ++__m;          // no need to check range on __m because __s guarantees we have enough source
1658            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1659            {
1660                __first = __m;
1661                ++__first;
1662                break;
1663            }  // else there is a match, check next elements
1664        }
1665    }
1666}
1667
1668template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
1669inline _LIBCPP_INLINE_VISIBILITY
1670_ForwardIterator
1671search_n(_ForwardIterator __first, _ForwardIterator __last,
1672         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
1673{
1674    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
1675           (__first, __last, __convert_to_integral(__count), __value_, __pred,
1676           typename iterator_traits<_ForwardIterator>::iterator_category());
1677}
1678
1679template <class _ForwardIterator, class _Size, class _Tp>
1680inline _LIBCPP_INLINE_VISIBILITY
1681_ForwardIterator
1682search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
1683{
1684    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1685    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
1686                           __value_, __equal_to<__v, _Tp>());
1687}
1688
1689// copy
1690
1691template <class _Iter>
1692struct __libcpp_is_trivial_iterator
1693{
1694    static const bool value = is_pointer<_Iter>::value;
1695};
1696
1697template <class _Iter>
1698struct __libcpp_is_trivial_iterator<move_iterator<_Iter> >
1699{
1700    static const bool value = is_pointer<_Iter>::value;
1701};
1702
1703template <class _Iter>
1704struct __libcpp_is_trivial_iterator<__wrap_iter<_Iter> >
1705{
1706    static const bool value = is_pointer<_Iter>::value;
1707};
1708
1709template <class _Iter>
1710inline _LIBCPP_INLINE_VISIBILITY
1711_Iter
1712__unwrap_iter(_Iter __i)
1713{
1714    return __i;
1715}
1716
1717template <class _Tp>
1718inline _LIBCPP_INLINE_VISIBILITY
1719typename enable_if
1720<
1721    is_trivially_copy_assignable<_Tp>::value,
1722    _Tp*
1723>::type
1724__unwrap_iter(move_iterator<_Tp*> __i)
1725{
1726    return __i.base();
1727}
1728
1729#if _LIBCPP_DEBUG_LEVEL < 2
1730
1731template <class _Tp>
1732inline _LIBCPP_INLINE_VISIBILITY
1733typename enable_if
1734<
1735    is_trivially_copy_assignable<_Tp>::value,
1736    _Tp*
1737>::type
1738__unwrap_iter(__wrap_iter<_Tp*> __i)
1739{
1740    return __i.base();
1741}
1742
1743#endif  // _LIBCPP_DEBUG_LEVEL < 2
1744
1745template <class _InputIterator, class _OutputIterator>
1746inline _LIBCPP_INLINE_VISIBILITY
1747_OutputIterator
1748__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1749{
1750    for (; __first != __last; ++__first, (void) ++__result)
1751        *__result = *__first;
1752    return __result;
1753}
1754
1755template <class _Tp, class _Up>
1756inline _LIBCPP_INLINE_VISIBILITY
1757typename enable_if
1758<
1759    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1760    is_trivially_copy_assignable<_Up>::value,
1761    _Up*
1762>::type
1763__copy(_Tp* __first, _Tp* __last, _Up* __result)
1764{
1765    const size_t __n = static_cast<size_t>(__last - __first);
1766    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1767    return __result + __n;
1768}
1769
1770template <class _InputIterator, class _OutputIterator>
1771inline _LIBCPP_INLINE_VISIBILITY
1772_OutputIterator
1773copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1774{
1775    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1776}
1777
1778// copy_backward
1779
1780template <class _BidirectionalIterator, class _OutputIterator>
1781inline _LIBCPP_INLINE_VISIBILITY
1782_OutputIterator
1783__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
1784{
1785    while (__first != __last)
1786        *--__result = *--__last;
1787    return __result;
1788}
1789
1790template <class _Tp, class _Up>
1791inline _LIBCPP_INLINE_VISIBILITY
1792typename enable_if
1793<
1794    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1795    is_trivially_copy_assignable<_Up>::value,
1796    _Up*
1797>::type
1798__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
1799{
1800    const size_t __n = static_cast<size_t>(__last - __first);
1801    __result -= __n;
1802    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1803    return __result;
1804}
1805
1806template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1807inline _LIBCPP_INLINE_VISIBILITY
1808_BidirectionalIterator2
1809copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1810              _BidirectionalIterator2 __result)
1811{
1812    return _VSTD::__copy_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1813}
1814
1815// copy_if
1816
1817template<class _InputIterator, class _OutputIterator, class _Predicate>
1818inline _LIBCPP_INLINE_VISIBILITY
1819_OutputIterator
1820copy_if(_InputIterator __first, _InputIterator __last,
1821        _OutputIterator __result, _Predicate __pred)
1822{
1823    for (; __first != __last; ++__first)
1824    {
1825        if (__pred(*__first))
1826        {
1827            *__result = *__first;
1828            ++__result;
1829        }
1830    }
1831    return __result;
1832}
1833
1834// copy_n
1835
1836template<class _InputIterator, class _Size, class _OutputIterator>
1837inline _LIBCPP_INLINE_VISIBILITY
1838typename enable_if
1839<
1840    __is_input_iterator<_InputIterator>::value &&
1841   !__is_random_access_iterator<_InputIterator>::value,
1842    _OutputIterator
1843>::type
1844copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1845{
1846    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1847    _IntegralSize __n = __orig_n;
1848    if (__n > 0)
1849    {
1850        *__result = *__first;
1851        ++__result;
1852        for (--__n; __n > 0; --__n)
1853        {
1854            ++__first;
1855            *__result = *__first;
1856            ++__result;
1857        }
1858    }
1859    return __result;
1860}
1861
1862template<class _InputIterator, class _Size, class _OutputIterator>
1863inline _LIBCPP_INLINE_VISIBILITY
1864typename enable_if
1865<
1866    __is_random_access_iterator<_InputIterator>::value,
1867    _OutputIterator
1868>::type
1869copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1870{
1871    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1872    _IntegralSize __n = __orig_n;
1873    return _VSTD::copy(__first, __first + __n, __result);
1874}
1875
1876// move
1877
1878template <class _InputIterator, class _OutputIterator>
1879inline _LIBCPP_INLINE_VISIBILITY
1880_OutputIterator
1881__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1882{
1883    for (; __first != __last; ++__first, (void) ++__result)
1884        *__result = _VSTD::move(*__first);
1885    return __result;
1886}
1887
1888template <class _Tp, class _Up>
1889inline _LIBCPP_INLINE_VISIBILITY
1890typename enable_if
1891<
1892    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1893    is_trivially_copy_assignable<_Up>::value,
1894    _Up*
1895>::type
1896__move(_Tp* __first, _Tp* __last, _Up* __result)
1897{
1898    const size_t __n = static_cast<size_t>(__last - __first);
1899    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1900    return __result + __n;
1901}
1902
1903template <class _InputIterator, class _OutputIterator>
1904inline _LIBCPP_INLINE_VISIBILITY
1905_OutputIterator
1906move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1907{
1908    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1909}
1910
1911// move_backward
1912
1913template <class _InputIterator, class _OutputIterator>
1914inline _LIBCPP_INLINE_VISIBILITY
1915_OutputIterator
1916__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1917{
1918    while (__first != __last)
1919        *--__result = _VSTD::move(*--__last);
1920    return __result;
1921}
1922
1923template <class _Tp, class _Up>
1924inline _LIBCPP_INLINE_VISIBILITY
1925typename enable_if
1926<
1927    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1928    is_trivially_copy_assignable<_Up>::value,
1929    _Up*
1930>::type
1931__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
1932{
1933    const size_t __n = static_cast<size_t>(__last - __first);
1934    __result -= __n;
1935    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1936    return __result;
1937}
1938
1939template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1940inline _LIBCPP_INLINE_VISIBILITY
1941_BidirectionalIterator2
1942move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1943              _BidirectionalIterator2 __result)
1944{
1945    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1946}
1947
1948// iter_swap
1949
1950// moved to <type_traits> for better swap / noexcept support
1951
1952// transform
1953
1954template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
1955inline _LIBCPP_INLINE_VISIBILITY
1956_OutputIterator
1957transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
1958{
1959    for (; __first != __last; ++__first, (void) ++__result)
1960        *__result = __op(*__first);
1961    return __result;
1962}
1963
1964template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
1965inline _LIBCPP_INLINE_VISIBILITY
1966_OutputIterator
1967transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
1968          _OutputIterator __result, _BinaryOperation __binary_op)
1969{
1970    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
1971        *__result = __binary_op(*__first1, *__first2);
1972    return __result;
1973}
1974
1975// replace
1976
1977template <class _ForwardIterator, class _Tp>
1978inline _LIBCPP_INLINE_VISIBILITY
1979void
1980replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
1981{
1982    for (; __first != __last; ++__first)
1983        if (*__first == __old_value)
1984            *__first = __new_value;
1985}
1986
1987// replace_if
1988
1989template <class _ForwardIterator, class _Predicate, class _Tp>
1990inline _LIBCPP_INLINE_VISIBILITY
1991void
1992replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
1993{
1994    for (; __first != __last; ++__first)
1995        if (__pred(*__first))
1996            *__first = __new_value;
1997}
1998
1999// replace_copy
2000
2001template <class _InputIterator, class _OutputIterator, class _Tp>
2002inline _LIBCPP_INLINE_VISIBILITY
2003_OutputIterator
2004replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2005             const _Tp& __old_value, const _Tp& __new_value)
2006{
2007    for (; __first != __last; ++__first, (void) ++__result)
2008        if (*__first == __old_value)
2009            *__result = __new_value;
2010        else
2011            *__result = *__first;
2012    return __result;
2013}
2014
2015// replace_copy_if
2016
2017template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
2018inline _LIBCPP_INLINE_VISIBILITY
2019_OutputIterator
2020replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2021                _Predicate __pred, const _Tp& __new_value)
2022{
2023    for (; __first != __last; ++__first, (void) ++__result)
2024        if (__pred(*__first))
2025            *__result = __new_value;
2026        else
2027            *__result = *__first;
2028    return __result;
2029}
2030
2031// fill_n
2032
2033template <class _OutputIterator, class _Size, class _Tp>
2034inline _LIBCPP_INLINE_VISIBILITY
2035_OutputIterator
2036__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2037{
2038    for (; __n > 0; ++__first, (void) --__n)
2039        *__first = __value_;
2040    return __first;
2041}
2042
2043template <class _Tp, class _Size, class _Up>
2044inline _LIBCPP_INLINE_VISIBILITY
2045typename enable_if
2046<
2047    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
2048    !is_same<_Tp, bool>::value &&
2049    is_integral<_Up>::value && sizeof(_Up) == 1,
2050    _Tp*
2051>::type
2052__fill_n(_Tp* __first, _Size __n,_Up __value_)
2053{
2054    if (__n > 0)
2055        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
2056    return __first + __n;
2057}
2058
2059template <class _OutputIterator, class _Size, class _Tp>
2060inline _LIBCPP_INLINE_VISIBILITY
2061_OutputIterator
2062fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2063{
2064   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
2065}
2066
2067// fill
2068
2069template <class _ForwardIterator, class _Tp>
2070inline _LIBCPP_INLINE_VISIBILITY
2071void
2072__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
2073{
2074    for (; __first != __last; ++__first)
2075        *__first = __value_;
2076}
2077
2078template <class _RandomAccessIterator, class _Tp>
2079inline _LIBCPP_INLINE_VISIBILITY
2080void
2081__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
2082{
2083    _VSTD::fill_n(__first, __last - __first, __value_);
2084}
2085
2086template <class _ForwardIterator, class _Tp>
2087inline _LIBCPP_INLINE_VISIBILITY
2088void
2089fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2090{
2091    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
2092}
2093
2094// generate
2095
2096template <class _ForwardIterator, class _Generator>
2097inline _LIBCPP_INLINE_VISIBILITY
2098void
2099generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
2100{
2101    for (; __first != __last; ++__first)
2102        *__first = __gen();
2103}
2104
2105// generate_n
2106
2107template <class _OutputIterator, class _Size, class _Generator>
2108inline _LIBCPP_INLINE_VISIBILITY
2109_OutputIterator
2110generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
2111{
2112    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
2113    _IntegralSize __n = __orig_n;
2114    for (; __n > 0; ++__first, (void) --__n)
2115        *__first = __gen();
2116    return __first;
2117}
2118
2119// remove
2120
2121template <class _ForwardIterator, class _Tp>
2122_ForwardIterator
2123remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2124{
2125    __first = _VSTD::find(__first, __last, __value_);
2126    if (__first != __last)
2127    {
2128        _ForwardIterator __i = __first;
2129        while (++__i != __last)
2130        {
2131            if (!(*__i == __value_))
2132            {
2133                *__first = _VSTD::move(*__i);
2134                ++__first;
2135            }
2136        }
2137    }
2138    return __first;
2139}
2140
2141// remove_if
2142
2143template <class _ForwardIterator, class _Predicate>
2144_ForwardIterator
2145remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2146{
2147    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
2148                           (__first, __last, __pred);
2149    if (__first != __last)
2150    {
2151        _ForwardIterator __i = __first;
2152        while (++__i != __last)
2153        {
2154            if (!__pred(*__i))
2155            {
2156                *__first = _VSTD::move(*__i);
2157                ++__first;
2158            }
2159        }
2160    }
2161    return __first;
2162}
2163
2164// remove_copy
2165
2166template <class _InputIterator, class _OutputIterator, class _Tp>
2167inline _LIBCPP_INLINE_VISIBILITY
2168_OutputIterator
2169remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
2170{
2171    for (; __first != __last; ++__first)
2172    {
2173        if (!(*__first == __value_))
2174        {
2175            *__result = *__first;
2176            ++__result;
2177        }
2178    }
2179    return __result;
2180}
2181
2182// remove_copy_if
2183
2184template <class _InputIterator, class _OutputIterator, class _Predicate>
2185inline _LIBCPP_INLINE_VISIBILITY
2186_OutputIterator
2187remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
2188{
2189    for (; __first != __last; ++__first)
2190    {
2191        if (!__pred(*__first))
2192        {
2193            *__result = *__first;
2194            ++__result;
2195        }
2196    }
2197    return __result;
2198}
2199
2200// unique
2201
2202template <class _ForwardIterator, class _BinaryPredicate>
2203_ForwardIterator
2204unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
2205{
2206    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
2207                                 (__first, __last, __pred);
2208    if (__first != __last)
2209    {
2210        // ...  a  a  ?  ...
2211        //      f     i
2212        _ForwardIterator __i = __first;
2213        for (++__i; ++__i != __last;)
2214            if (!__pred(*__first, *__i))
2215                *++__first = _VSTD::move(*__i);
2216        ++__first;
2217    }
2218    return __first;
2219}
2220
2221template <class _ForwardIterator>
2222inline _LIBCPP_INLINE_VISIBILITY
2223_ForwardIterator
2224unique(_ForwardIterator __first, _ForwardIterator __last)
2225{
2226    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
2227    return _VSTD::unique(__first, __last, __equal_to<__v>());
2228}
2229
2230// unique_copy
2231
2232template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
2233_OutputIterator
2234__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2235              input_iterator_tag, output_iterator_tag)
2236{
2237    if (__first != __last)
2238    {
2239        typename iterator_traits<_InputIterator>::value_type __t(*__first);
2240        *__result = __t;
2241        ++__result;
2242        while (++__first != __last)
2243        {
2244            if (!__pred(__t, *__first))
2245            {
2246                __t = *__first;
2247                *__result = __t;
2248                ++__result;
2249            }
2250        }
2251    }
2252    return __result;
2253}
2254
2255template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
2256_OutputIterator
2257__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2258              forward_iterator_tag, output_iterator_tag)
2259{
2260    if (__first != __last)
2261    {
2262        _ForwardIterator __i = __first;
2263        *__result = *__i;
2264        ++__result;
2265        while (++__first != __last)
2266        {
2267            if (!__pred(*__i, *__first))
2268            {
2269                *__result = *__first;
2270                ++__result;
2271                __i = __first;
2272            }
2273        }
2274    }
2275    return __result;
2276}
2277
2278template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
2279_ForwardIterator
2280__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
2281              input_iterator_tag, forward_iterator_tag)
2282{
2283    if (__first != __last)
2284    {
2285        *__result = *__first;
2286        while (++__first != __last)
2287            if (!__pred(*__result, *__first))
2288                *++__result = *__first;
2289        ++__result;
2290    }
2291    return __result;
2292}
2293
2294template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
2295inline _LIBCPP_INLINE_VISIBILITY
2296_OutputIterator
2297unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
2298{
2299    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
2300                              (__first, __last, __result, __pred,
2301                               typename iterator_traits<_InputIterator>::iterator_category(),
2302                               typename iterator_traits<_OutputIterator>::iterator_category());
2303}
2304
2305template <class _InputIterator, class _OutputIterator>
2306inline _LIBCPP_INLINE_VISIBILITY
2307_OutputIterator
2308unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
2309{
2310    typedef typename iterator_traits<_InputIterator>::value_type __v;
2311    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
2312}
2313
2314// reverse
2315
2316template <class _BidirectionalIterator>
2317inline _LIBCPP_INLINE_VISIBILITY
2318void
2319__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
2320{
2321    while (__first != __last)
2322    {
2323        if (__first == --__last)
2324            break;
2325        swap(*__first, *__last);
2326        ++__first;
2327    }
2328}
2329
2330template <class _RandomAccessIterator>
2331inline _LIBCPP_INLINE_VISIBILITY
2332void
2333__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
2334{
2335    if (__first != __last)
2336        for (; __first < --__last; ++__first)
2337            swap(*__first, *__last);
2338}
2339
2340template <class _BidirectionalIterator>
2341inline _LIBCPP_INLINE_VISIBILITY
2342void
2343reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
2344{
2345    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
2346}
2347
2348// reverse_copy
2349
2350template <class _BidirectionalIterator, class _OutputIterator>
2351inline _LIBCPP_INLINE_VISIBILITY
2352_OutputIterator
2353reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
2354{
2355    for (; __first != __last; ++__result)
2356        *__result = *--__last;
2357    return __result;
2358}
2359
2360// rotate
2361
2362template <class _ForwardIterator>
2363_ForwardIterator
2364__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
2365{
2366    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
2367    value_type __tmp = _VSTD::move(*__first);
2368    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
2369    *__lm1 = _VSTD::move(__tmp);
2370    return __lm1;
2371}
2372
2373template <class _BidirectionalIterator>
2374_BidirectionalIterator
2375__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
2376{
2377    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
2378    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
2379    value_type __tmp = _VSTD::move(*__lm1);
2380    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
2381    *__first = _VSTD::move(__tmp);
2382    return __fp1;
2383}
2384
2385template <class _ForwardIterator>
2386_ForwardIterator
2387__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2388{
2389    _ForwardIterator __i = __middle;
2390    while (true)
2391    {
2392        swap(*__first, *__i);
2393        ++__first;
2394        if (++__i == __last)
2395            break;
2396        if (__first == __middle)
2397            __middle = __i;
2398    }
2399    _ForwardIterator __r = __first;
2400    if (__first != __middle)
2401    {
2402        __i = __middle;
2403        while (true)
2404        {
2405            swap(*__first, *__i);
2406            ++__first;
2407            if (++__i == __last)
2408            {
2409                if (__first == __middle)
2410                    break;
2411                __i = __middle;
2412            }
2413            else if (__first == __middle)
2414                __middle = __i;
2415        }
2416    }
2417    return __r;
2418}
2419
2420template<typename _Integral>
2421inline _LIBCPP_INLINE_VISIBILITY
2422_Integral
2423__gcd(_Integral __x, _Integral __y)
2424{
2425    do
2426    {
2427        _Integral __t = __x % __y;
2428        __x = __y;
2429        __y = __t;
2430    } while (__y);
2431    return __x;
2432}
2433
2434template<typename _RandomAccessIterator>
2435_RandomAccessIterator
2436__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
2437{
2438    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
2439    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
2440
2441    const difference_type __m1 = __middle - __first;
2442    const difference_type __m2 = __last - __middle;
2443    if (__m1 == __m2)
2444    {
2445        _VSTD::swap_ranges(__first, __middle, __middle);
2446        return __middle;
2447    }
2448    const difference_type __g = _VSTD::__gcd(__m1, __m2);
2449    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
2450    {
2451        value_type __t(_VSTD::move(*--__p));
2452        _RandomAccessIterator __p1 = __p;
2453        _RandomAccessIterator __p2 = __p1 + __m1;
2454        do
2455        {
2456            *__p1 = _VSTD::move(*__p2);
2457            __p1 = __p2;
2458            const difference_type __d = __last - __p2;
2459            if (__m1 < __d)
2460                __p2 += __m1;
2461            else
2462                __p2 = __first + (__m1 - __d);
2463        } while (__p2 != __p);
2464        *__p1 = _VSTD::move(__t);
2465    }
2466    return __first + __m2;
2467}
2468
2469template <class _ForwardIterator>
2470inline _LIBCPP_INLINE_VISIBILITY
2471_ForwardIterator
2472__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
2473         _VSTD::forward_iterator_tag)
2474{
2475    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
2476    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2477    {
2478        if (_VSTD::next(__first) == __middle)
2479            return _VSTD::__rotate_left(__first, __last);
2480    }
2481    return _VSTD::__rotate_forward(__first, __middle, __last);
2482}
2483
2484template <class _BidirectionalIterator>
2485inline _LIBCPP_INLINE_VISIBILITY
2486_BidirectionalIterator
2487__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
2488         _VSTD::bidirectional_iterator_tag)
2489{
2490    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
2491    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2492    {
2493        if (_VSTD::next(__first) == __middle)
2494            return _VSTD::__rotate_left(__first, __last);
2495        if (_VSTD::next(__middle) == __last)
2496            return _VSTD::__rotate_right(__first, __last);
2497    }
2498    return _VSTD::__rotate_forward(__first, __middle, __last);
2499}
2500
2501template <class _RandomAccessIterator>
2502inline _LIBCPP_INLINE_VISIBILITY
2503_RandomAccessIterator
2504__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
2505         _VSTD::random_access_iterator_tag)
2506{
2507    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
2508    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2509    {
2510        if (_VSTD::next(__first) == __middle)
2511            return _VSTD::__rotate_left(__first, __last);
2512        if (_VSTD::next(__middle) == __last)
2513            return _VSTD::__rotate_right(__first, __last);
2514        return _VSTD::__rotate_gcd(__first, __middle, __last);
2515    }
2516    return _VSTD::__rotate_forward(__first, __middle, __last);
2517}
2518
2519template <class _ForwardIterator>
2520inline _LIBCPP_INLINE_VISIBILITY
2521_ForwardIterator
2522rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2523{
2524    if (__first == __middle)
2525        return __last;
2526    if (__middle == __last)
2527        return __first;
2528    return _VSTD::__rotate(__first, __middle, __last,
2529                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
2530}
2531
2532// rotate_copy
2533
2534template <class _ForwardIterator, class _OutputIterator>
2535inline _LIBCPP_INLINE_VISIBILITY
2536_OutputIterator
2537rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
2538{
2539    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
2540}
2541
2542// min_element
2543
2544template <class _ForwardIterator, class _Compare>
2545inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2546_ForwardIterator
2547__min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2548{
2549    if (__first != __last)
2550    {
2551        _ForwardIterator __i = __first;
2552        while (++__i != __last)
2553            if (__comp(*__i, *__first))
2554                __first = __i;
2555    }
2556    return __first;
2557}
2558
2559template <class _ForwardIterator, class _Compare>
2560inline _LIBCPP_INLINE_VISIBILITY
2561_ForwardIterator
2562min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2563{
2564    return __min_element(__first, __last, __comp);
2565}
2566
2567template <class _ForwardIterator>
2568inline _LIBCPP_INLINE_VISIBILITY
2569_ForwardIterator
2570min_element(_ForwardIterator __first, _ForwardIterator __last)
2571{
2572    return __min_element(__first, __last,
2573              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2574}
2575
2576// min
2577
2578template <class _Tp, class _Compare>
2579inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2580const _Tp&
2581min(const _Tp& __a, const _Tp& __b, _Compare __comp)
2582{
2583    return __comp(__b, __a) ? __b : __a;
2584}
2585
2586template <class _Tp>
2587inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2588const _Tp&
2589min(const _Tp& __a, const _Tp& __b)
2590{
2591    return _VSTD::min(__a, __b, __less<_Tp>());
2592}
2593
2594#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2595
2596template<class _Tp, class _Compare>
2597inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2598_Tp
2599min(initializer_list<_Tp> __t, _Compare __comp)
2600{
2601    return *__min_element(__t.begin(), __t.end(), __comp);
2602}
2603
2604template<class _Tp>
2605inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2606_Tp
2607min(initializer_list<_Tp> __t)
2608{
2609    return *__min_element(__t.begin(), __t.end(), __less<_Tp>());
2610}
2611
2612#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2613
2614// max_element
2615
2616template <class _ForwardIterator, class _Compare>
2617inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2618_ForwardIterator
2619__max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2620{
2621    if (__first != __last)
2622    {
2623        _ForwardIterator __i = __first;
2624        while (++__i != __last)
2625            if (__comp(*__first, *__i))
2626                __first = __i;
2627    }
2628    return __first;
2629}
2630
2631
2632template <class _ForwardIterator, class _Compare>
2633inline _LIBCPP_INLINE_VISIBILITY
2634_ForwardIterator
2635max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2636{
2637    return __max_element(__first, __last, __comp);
2638}
2639
2640template <class _ForwardIterator>
2641inline _LIBCPP_INLINE_VISIBILITY
2642_ForwardIterator
2643max_element(_ForwardIterator __first, _ForwardIterator __last)
2644{
2645    return __max_element(__first, __last,
2646              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2647}
2648
2649// max
2650
2651template <class _Tp, class _Compare>
2652inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2653const _Tp&
2654max(const _Tp& __a, const _Tp& __b, _Compare __comp)
2655{
2656    return __comp(__a, __b) ? __b : __a;
2657}
2658
2659template <class _Tp>
2660inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2661const _Tp&
2662max(const _Tp& __a, const _Tp& __b)
2663{
2664    return _VSTD::max(__a, __b, __less<_Tp>());
2665}
2666
2667#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2668
2669template<class _Tp, class _Compare>
2670inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2671_Tp
2672max(initializer_list<_Tp> __t, _Compare __comp)
2673{
2674    return *__max_element(__t.begin(), __t.end(), __comp);
2675}
2676
2677template<class _Tp>
2678inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2679_Tp
2680max(initializer_list<_Tp> __t)
2681{
2682    return *__max_element(__t.begin(), __t.end(), __less<_Tp>());
2683}
2684
2685#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2686
2687// minmax_element
2688
2689template <class _ForwardIterator, class _Compare>
2690std::pair<_ForwardIterator, _ForwardIterator>
2691minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2692{
2693  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
2694  if (__first != __last)
2695  {
2696      if (++__first != __last)
2697      {
2698          if (__comp(*__first, *__result.first))
2699              __result.first = __first;
2700          else
2701              __result.second = __first;
2702          while (++__first != __last)
2703          {
2704              _ForwardIterator __i = __first;
2705              if (++__first == __last)
2706              {
2707                  if (__comp(*__i, *__result.first))
2708                      __result.first = __i;
2709                  else if (!__comp(*__i, *__result.second))
2710                      __result.second = __i;
2711                  break;
2712              }
2713              else
2714              {
2715                  if (__comp(*__first, *__i))
2716                  {
2717                      if (__comp(*__first, *__result.first))
2718                          __result.first = __first;
2719                      if (!__comp(*__i, *__result.second))
2720                          __result.second = __i;
2721                  }
2722                  else
2723                  {
2724                      if (__comp(*__i, *__result.first))
2725                          __result.first = __i;
2726                      if (!__comp(*__first, *__result.second))
2727                          __result.second = __first;
2728                  }
2729              }
2730          }
2731      }
2732  }
2733  return __result;
2734}
2735
2736template <class _ForwardIterator>
2737inline _LIBCPP_INLINE_VISIBILITY
2738std::pair<_ForwardIterator, _ForwardIterator>
2739minmax_element(_ForwardIterator __first, _ForwardIterator __last)
2740{
2741    return _VSTD::minmax_element(__first, __last,
2742              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2743}
2744
2745// minmax
2746
2747template<class _Tp, class _Compare>
2748inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2749pair<const _Tp&, const _Tp&>
2750minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
2751{
2752    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
2753                              pair<const _Tp&, const _Tp&>(__a, __b);
2754}
2755
2756template<class _Tp>
2757inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2758pair<const _Tp&, const _Tp&>
2759minmax(const _Tp& __a, const _Tp& __b)
2760{
2761    return _VSTD::minmax(__a, __b, __less<_Tp>());
2762}
2763
2764#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2765
2766template<class _Tp, class _Compare>
2767inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2768pair<_Tp, _Tp>
2769minmax(initializer_list<_Tp> __t, _Compare __comp)
2770{
2771    typedef typename initializer_list<_Tp>::const_iterator _Iter;
2772    _Iter __first = __t.begin();
2773    _Iter __last  = __t.end();
2774    std::pair<_Tp, _Tp> __result(*__first, *__first);
2775
2776    ++__first;
2777    if (__t.size() % 2 == 0)
2778    {
2779        if (__comp(*__first,  __result.first))
2780            __result.first  = *__first;
2781        else
2782            __result.second = *__first;
2783        ++__first;
2784    }
2785    
2786    while (__first != __last)
2787    {
2788        _Tp __prev = *__first++;
2789        if (__comp(*__first, __prev)) {
2790            if ( __comp(*__first, __result.first)) __result.first  = *__first;
2791            if (!__comp(__prev, __result.second))  __result.second = __prev;
2792            }
2793        else {
2794            if ( __comp(__prev, __result.first))    __result.first  = __prev;
2795            if (!__comp(*__first, __result.second)) __result.second = *__first;
2796            }
2797                
2798        __first++;
2799    }
2800    return __result;
2801}
2802
2803template<class _Tp>
2804inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2805pair<_Tp, _Tp>
2806minmax(initializer_list<_Tp> __t)
2807{
2808    return _VSTD::minmax(__t, __less<_Tp>());
2809}
2810
2811#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2812
2813// random_shuffle
2814
2815// __independent_bits_engine
2816
2817template <unsigned long long _Xp, size_t _Rp>
2818struct __log2_imp
2819{
2820    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
2821                                           : __log2_imp<_Xp, _Rp - 1>::value;
2822};
2823
2824template <unsigned long long _Xp>
2825struct __log2_imp<_Xp, 0>
2826{
2827    static const size_t value = 0;
2828};
2829
2830template <size_t _Rp>
2831struct __log2_imp<0, _Rp>
2832{
2833    static const size_t value = _Rp + 1;
2834};
2835
2836template <class _UI, _UI _Xp>
2837struct __log2
2838{
2839    static const size_t value = __log2_imp<_Xp,
2840                                         sizeof(_UI) * __CHAR_BIT__ - 1>::value;
2841};
2842
2843template<class _Engine, class _UIntType>
2844class __independent_bits_engine
2845{
2846public:
2847    // types
2848    typedef _UIntType result_type;
2849
2850private:
2851    typedef typename _Engine::result_type _Engine_result_type;
2852    typedef typename conditional
2853        <
2854            sizeof(_Engine_result_type) <= sizeof(result_type),
2855                result_type,
2856                _Engine_result_type
2857        >::type _Working_result_type;
2858
2859    _Engine& __e_;
2860    size_t __w_;
2861    size_t __w0_;
2862    size_t __n_;
2863    size_t __n0_;
2864    _Working_result_type __y0_;
2865    _Working_result_type __y1_;
2866    _Engine_result_type __mask0_;
2867    _Engine_result_type __mask1_;
2868
2869#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2870    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2871                                          + _Working_result_type(1);
2872#else
2873    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2874                                                      + _Working_result_type(1);
2875#endif
2876    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2877    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2878    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2879
2880public:
2881    // constructors and seeding functions
2882    __independent_bits_engine(_Engine& __e, size_t __w);
2883
2884    // generating functions
2885    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2886
2887private:
2888    result_type __eval(false_type);
2889    result_type __eval(true_type);
2890};
2891
2892template<class _Engine, class _UIntType>
2893__independent_bits_engine<_Engine, _UIntType>
2894    ::__independent_bits_engine(_Engine& __e, size_t __w)
2895        : __e_(__e),
2896          __w_(__w)
2897{
2898    __n_ = __w_ / __m + (__w_ % __m != 0);
2899    __w0_ = __w_ / __n_;
2900    if (_Rp == 0)
2901        __y0_ = _Rp;
2902    else if (__w0_ < _WDt)
2903        __y0_ = (_Rp >> __w0_) << __w0_;
2904    else
2905        __y0_ = 0;
2906    if (_Rp - __y0_ > __y0_ / __n_)
2907    {
2908        ++__n_;
2909        __w0_ = __w_ / __n_;
2910        if (__w0_ < _WDt)
2911            __y0_ = (_Rp >> __w0_) << __w0_;
2912        else
2913            __y0_ = 0;
2914    }
2915    __n0_ = __n_ - __w_ % __n_;
2916    if (__w0_ < _WDt - 1)
2917        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
2918    else
2919        __y1_ = 0;
2920    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
2921                          _Engine_result_type(0);
2922    __mask1_ = __w0_ < _EDt - 1 ?
2923                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
2924                               _Engine_result_type(~0);
2925}
2926
2927template<class _Engine, class _UIntType>
2928inline
2929_UIntType
2930__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
2931{
2932    return static_cast<result_type>(__e_() & __mask0_);
2933}
2934
2935template<class _Engine, class _UIntType>
2936_UIntType
2937__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
2938{
2939    result_type _Sp = 0;
2940    for (size_t __k = 0; __k < __n0_; ++__k)
2941    {
2942        _Engine_result_type __u;
2943        do
2944        {
2945            __u = __e_() - _Engine::min();
2946        } while (__u >= __y0_);
2947        if (__w0_ < _WDt)
2948            _Sp <<= __w0_;
2949        else
2950            _Sp = 0;
2951        _Sp += __u & __mask0_;
2952    }
2953    for (size_t __k = __n0_; __k < __n_; ++__k)
2954    {
2955        _Engine_result_type __u;
2956        do
2957        {
2958            __u = __e_() - _Engine::min();
2959        } while (__u >= __y1_);
2960        if (__w0_ < _WDt - 1)
2961            _Sp <<= __w0_ + 1;
2962        else
2963            _Sp = 0;
2964        _Sp += __u & __mask1_;
2965    }
2966    return _Sp;
2967}
2968
2969// uniform_int_distribution
2970
2971template<class _IntType = int>
2972class uniform_int_distribution
2973{
2974public:
2975    // types
2976    typedef _IntType result_type;
2977
2978    class param_type
2979    {
2980        result_type __a_;
2981        result_type __b_;
2982    public:
2983        typedef uniform_int_distribution distribution_type;
2984
2985        explicit param_type(result_type __a = 0,
2986                            result_type __b = numeric_limits<result_type>::max())
2987            : __a_(__a), __b_(__b) {}
2988
2989        result_type a() const {return __a_;}
2990        result_type b() const {return __b_;}
2991
2992        friend bool operator==(const param_type& __x, const param_type& __y)
2993            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
2994        friend bool operator!=(const param_type& __x, const param_type& __y)
2995            {return !(__x == __y);}
2996    };
2997
2998private:
2999    param_type __p_;
3000
3001public:
3002    // constructors and reset functions
3003    explicit uniform_int_distribution(result_type __a = 0,
3004                                      result_type __b = numeric_limits<result_type>::max())
3005        : __p_(param_type(__a, __b)) {}
3006    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
3007    void reset() {}
3008
3009    // generating functions
3010    template<class _URNG> result_type operator()(_URNG& __g)
3011        {return (*this)(__g, __p_);}
3012    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3013
3014    // property functions
3015    result_type a() const {return __p_.a();}
3016    result_type b() const {return __p_.b();}
3017
3018    param_type param() const {return __p_;}
3019    void param(const param_type& __p) {__p_ = __p;}
3020
3021    result_type min() const {return a();}
3022    result_type max() const {return b();}
3023
3024    friend bool operator==(const uniform_int_distribution& __x,
3025                           const uniform_int_distribution& __y)
3026        {return __x.__p_ == __y.__p_;}
3027    friend bool operator!=(const uniform_int_distribution& __x,
3028                           const uniform_int_distribution& __y)
3029            {return !(__x == __y);}
3030};
3031
3032template<class _IntType>
3033template<class _URNG>
3034typename uniform_int_distribution<_IntType>::result_type
3035uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
3036{
3037    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
3038                                            uint32_t, uint64_t>::type _UIntType;
3039    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
3040    if (_Rp == 1)
3041        return __p.a();
3042    const size_t _Dt = numeric_limits<_UIntType>::digits;
3043    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
3044    if (_Rp == 0)
3045        return static_cast<result_type>(_Eng(__g, _Dt)());
3046    size_t __w = _Dt - __clz(_Rp) - 1;
3047    if ((_Rp & (_UIntType(~0) >> (_Dt - __w))) != 0)
3048        ++__w;
3049    _Eng __e(__g, __w);
3050    _UIntType __u;
3051    do
3052    {
3053        __u = __e();
3054    } while (__u >= _Rp);
3055    return static_cast<result_type>(__u + __p.a());
3056}
3057
3058class _LIBCPP_TYPE_VIS __rs_default;
3059
3060_LIBCPP_FUNC_VIS __rs_default __rs_get();
3061
3062class _LIBCPP_TYPE_VIS __rs_default
3063{
3064    static unsigned __c_;
3065
3066    __rs_default();
3067public:
3068    typedef uint_fast32_t result_type;
3069
3070    static const result_type _Min = 0;
3071    static const result_type _Max = 0xFFFFFFFF;
3072
3073    __rs_default(const __rs_default&);
3074    ~__rs_default();
3075
3076    result_type operator()();
3077
3078    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
3079    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
3080
3081    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
3082};
3083
3084_LIBCPP_FUNC_VIS __rs_default __rs_get();
3085
3086template <class _RandomAccessIterator>
3087void
3088random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
3089{
3090    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3091    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3092    typedef typename _Dp::param_type _Pp;
3093    difference_type __d = __last - __first;
3094    if (__d > 1)
3095    {
3096        _Dp __uid;
3097        __rs_default __g = __rs_get();
3098        for (--__last, --__d; __first < __last; ++__first, --__d)
3099        {
3100            difference_type __i = __uid(__g, _Pp(0, __d));
3101            if (__i != difference_type(0))
3102                swap(*__first, *(__first + __i));
3103        }
3104    }
3105}
3106
3107template <class _RandomAccessIterator, class _RandomNumberGenerator>
3108void
3109random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3110#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3111               _RandomNumberGenerator&& __rand)
3112#else
3113               _RandomNumberGenerator& __rand)
3114#endif
3115{
3116    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3117    difference_type __d = __last - __first;
3118    if (__d > 1)
3119    {
3120        for (--__last; __first < __last; ++__first, --__d)
3121        {
3122            difference_type __i = __rand(__d);
3123            swap(*__first, *(__first + __i));
3124        }
3125    }
3126}
3127
3128template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
3129    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3130#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3131                 _UniformRandomNumberGenerator&& __g)
3132#else
3133                 _UniformRandomNumberGenerator& __g)
3134#endif
3135{
3136    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3137    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3138    typedef typename _Dp::param_type _Pp;
3139    difference_type __d = __last - __first;
3140    if (__d > 1)
3141    {
3142        _Dp __uid;
3143        for (--__last, --__d; __first < __last; ++__first, --__d)
3144        {
3145            difference_type __i = __uid(__g, _Pp(0, __d));
3146            if (__i != difference_type(0))
3147                swap(*__first, *(__first + __i));
3148        }
3149    }
3150}
3151
3152template <class _InputIterator, class _Predicate>
3153bool
3154is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3155{
3156    for (; __first != __last; ++__first)
3157        if (!__pred(*__first))
3158            break;
3159    if ( __first == __last )
3160        return true;
3161    ++__first;
3162    for (; __first != __last; ++__first)
3163        if (__pred(*__first))
3164            return false;
3165    return true;
3166}
3167
3168// partition
3169
3170template <class _Predicate, class _ForwardIterator>
3171_ForwardIterator
3172__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
3173{
3174    while (true)
3175    {
3176        if (__first == __last)
3177            return __first;
3178        if (!__pred(*__first))
3179            break;
3180        ++__first;
3181    }
3182    for (_ForwardIterator __p = __first; ++__p != __last;)
3183    {
3184        if (__pred(*__p))
3185        {
3186            swap(*__first, *__p);
3187            ++__first;
3188        }
3189    }
3190    return __first;
3191}
3192
3193template <class _Predicate, class _BidirectionalIterator>
3194_BidirectionalIterator
3195__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3196            bidirectional_iterator_tag)
3197{
3198    while (true)
3199    {
3200        while (true)
3201        {
3202            if (__first == __last)
3203                return __first;
3204            if (!__pred(*__first))
3205                break;
3206            ++__first;
3207        }
3208        do
3209        {
3210            if (__first == --__last)
3211                return __first;
3212        } while (!__pred(*__last));
3213        swap(*__first, *__last);
3214        ++__first;
3215    }
3216}
3217
3218template <class _ForwardIterator, class _Predicate>
3219inline _LIBCPP_INLINE_VISIBILITY
3220_ForwardIterator
3221partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3222{
3223    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
3224                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3225}
3226
3227// partition_copy
3228
3229template <class _InputIterator, class _OutputIterator1,
3230          class _OutputIterator2, class _Predicate>
3231pair<_OutputIterator1, _OutputIterator2>
3232partition_copy(_InputIterator __first, _InputIterator __last,
3233               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
3234               _Predicate __pred)
3235{
3236    for (; __first != __last; ++__first)
3237    {
3238        if (__pred(*__first))
3239        {
3240            *__out_true = *__first;
3241            ++__out_true;
3242        }
3243        else
3244        {
3245            *__out_false = *__first;
3246            ++__out_false;
3247        }
3248    }
3249    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
3250}
3251
3252// partition_point
3253
3254template<class _ForwardIterator, class _Predicate>
3255_ForwardIterator
3256partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3257{
3258    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3259    difference_type __len = _VSTD::distance(__first, __last);
3260    while (__len != 0)
3261    {
3262        difference_type __l2 = __len / 2;
3263        _ForwardIterator __m = __first;
3264        _VSTD::advance(__m, __l2);
3265        if (__pred(*__m))
3266        {
3267            __first = ++__m;
3268            __len -= __l2 + 1;
3269        }
3270        else
3271            __len = __l2;
3272    }
3273    return __first;
3274}
3275
3276// stable_partition
3277
3278template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
3279_ForwardIterator
3280__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3281                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
3282{
3283    // *__first is known to be false
3284    // __len >= 1
3285    if (__len == 1)
3286        return __first;
3287    if (__len == 2)
3288    {
3289        _ForwardIterator __m = __first;
3290        if (__pred(*++__m))
3291        {
3292            swap(*__first, *__m);
3293            return __m;
3294        }
3295        return __first;
3296    }
3297    if (__len <= __p.second)
3298    {   // The buffer is big enough to use
3299        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3300        __destruct_n __d(0);
3301        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3302        // Move the falses into the temporary buffer, and the trues to the front of the line
3303        // Update __first to always point to the end of the trues
3304        value_type* __t = __p.first;
3305        ::new(__t) value_type(_VSTD::move(*__first));
3306        __d.__incr((value_type*)0);
3307        ++__t;
3308        _ForwardIterator __i = __first;
3309        while (++__i != __last)
3310        {
3311            if (__pred(*__i))
3312            {
3313                *__first = _VSTD::move(*__i);
3314                ++__first;
3315            }
3316            else
3317            {
3318                ::new(__t) value_type(_VSTD::move(*__i));
3319                __d.__incr((value_type*)0);
3320                ++__t;
3321            }
3322        }
3323        // All trues now at start of range, all falses in buffer
3324        // Move falses back into range, but don't mess up __first which points to first false
3325        __i = __first;
3326        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3327            *__i = _VSTD::move(*__t2);
3328        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3329        return __first;
3330    }
3331    // Else not enough buffer, do in place
3332    // __len >= 3
3333    _ForwardIterator __m = __first;
3334    _Distance __len2 = __len / 2;  // __len2 >= 2
3335    _VSTD::advance(__m, __len2);
3336    // recurse on [__first, __m), *__first know to be false
3337    // F?????????????????
3338    // f       m         l
3339    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3340    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
3341    // TTTFFFFF??????????
3342    // f  ff   m         l
3343    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3344    _ForwardIterator __m1 = __m;
3345    _ForwardIterator __second_false = __last;
3346    _Distance __len_half = __len - __len2;
3347    while (__pred(*__m1))
3348    {
3349        if (++__m1 == __last)
3350            goto __second_half_done;
3351        --__len_half;
3352    }
3353    // TTTFFFFFTTTF??????
3354    // f  ff   m  m1     l
3355    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
3356__second_half_done:
3357    // TTTFFFFFTTTTTFFFFF
3358    // f  ff   m    sf   l
3359    return _VSTD::rotate(__first_false, __m, __second_false);
3360    // TTTTTTTTFFFFFFFFFF
3361    //         |
3362}
3363
3364struct __return_temporary_buffer
3365{
3366    template <class _Tp>
3367    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
3368};
3369
3370template <class _Predicate, class _ForwardIterator>
3371_ForwardIterator
3372__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3373                   forward_iterator_tag)
3374{
3375    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
3376    // Either prove all true and return __first or point to first false
3377    while (true)
3378    {
3379        if (__first == __last)
3380            return __first;
3381        if (!__pred(*__first))
3382            break;
3383        ++__first;
3384    }
3385    // We now have a reduced range [__first, __last)
3386    // *__first is known to be false
3387    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3388    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3389    difference_type __len = _VSTD::distance(__first, __last);
3390    pair<value_type*, ptrdiff_t> __p(0, 0);
3391    unique_ptr<value_type, __return_temporary_buffer> __h;
3392    if (__len >= __alloc_limit)
3393    {
3394        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3395        __h.reset(__p.first);
3396    }
3397    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3398                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
3399}
3400
3401template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
3402_BidirectionalIterator
3403__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3404                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
3405{
3406    // *__first is known to be false
3407    // *__last is known to be true
3408    // __len >= 2
3409    if (__len == 2)
3410    {
3411        swap(*__first, *__last);
3412        return __last;
3413    }
3414    if (__len == 3)
3415    {
3416        _BidirectionalIterator __m = __first;
3417        if (__pred(*++__m))
3418        {
3419            swap(*__first, *__m);
3420            swap(*__m, *__last);
3421            return __last;
3422        }
3423        swap(*__m, *__last);
3424        swap(*__first, *__m);
3425        return __m;
3426    }
3427    if (__len <= __p.second)
3428    {   // The buffer is big enough to use
3429        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3430        __destruct_n __d(0);
3431        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3432        // Move the falses into the temporary buffer, and the trues to the front of the line
3433        // Update __first to always point to the end of the trues
3434        value_type* __t = __p.first;
3435        ::new(__t) value_type(_VSTD::move(*__first));
3436        __d.__incr((value_type*)0);
3437        ++__t;
3438        _BidirectionalIterator __i = __first;
3439        while (++__i != __last)
3440        {
3441            if (__pred(*__i))
3442            {
3443                *__first = _VSTD::move(*__i);
3444                ++__first;
3445            }
3446            else
3447            {
3448                ::new(__t) value_type(_VSTD::move(*__i));
3449                __d.__incr((value_type*)0);
3450                ++__t;
3451            }
3452        }
3453        // move *__last, known to be true
3454        *__first = _VSTD::move(*__i);
3455        __i = ++__first;
3456        // All trues now at start of range, all falses in buffer
3457        // Move falses back into range, but don't mess up __first which points to first false
3458        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3459            *__i = _VSTD::move(*__t2);
3460        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3461        return __first;
3462    }
3463    // Else not enough buffer, do in place
3464    // __len >= 4
3465    _BidirectionalIterator __m = __first;
3466    _Distance __len2 = __len / 2;  // __len2 >= 2
3467    _VSTD::advance(__m, __len2);
3468    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
3469    // F????????????????T
3470    // f       m        l
3471    _BidirectionalIterator __m1 = __m;
3472    _BidirectionalIterator __first_false = __first;
3473    _Distance __len_half = __len2;
3474    while (!__pred(*--__m1))
3475    {
3476        if (__m1 == __first)
3477            goto __first_half_done;
3478        --__len_half;
3479    }
3480    // F???TFFF?????????T
3481    // f   m1  m        l
3482    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3483    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
3484__first_half_done:
3485    // TTTFFFFF?????????T
3486    // f  ff   m        l
3487    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3488    __m1 = __m;
3489    _BidirectionalIterator __second_false = __last;
3490    ++__second_false;
3491    __len_half = __len - __len2;
3492    while (__pred(*__m1))
3493    {
3494        if (++__m1 == __last)
3495            goto __second_half_done;
3496        --__len_half;
3497    }
3498    // TTTFFFFFTTTF?????T
3499    // f  ff   m  m1    l
3500    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
3501__second_half_done:
3502    // TTTFFFFFTTTTTFFFFF
3503    // f  ff   m    sf  l
3504    return _VSTD::rotate(__first_false, __m, __second_false);
3505    // TTTTTTTTFFFFFFFFFF
3506    //         |
3507}
3508
3509template <class _Predicate, class _BidirectionalIterator>
3510_BidirectionalIterator
3511__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3512                   bidirectional_iterator_tag)
3513{
3514    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
3515    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3516    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
3517    // Either prove all true and return __first or point to first false
3518    while (true)
3519    {
3520        if (__first == __last)
3521            return __first;
3522        if (!__pred(*__first))
3523            break;
3524        ++__first;
3525    }
3526    // __first points to first false, everything prior to __first is already set.
3527    // Either prove [__first, __last) is all false and return __first, or point __last to last true
3528    do
3529    {
3530        if (__first == --__last)
3531            return __first;
3532    } while (!__pred(*__last));
3533    // We now have a reduced range [__first, __last]
3534    // *__first is known to be false
3535    // *__last is known to be true
3536    // __len >= 2
3537    difference_type __len = _VSTD::distance(__first, __last) + 1;
3538    pair<value_type*, ptrdiff_t> __p(0, 0);
3539    unique_ptr<value_type, __return_temporary_buffer> __h;
3540    if (__len >= __alloc_limit)
3541    {
3542        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3543        __h.reset(__p.first);
3544    }
3545    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3546                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
3547}
3548
3549template <class _ForwardIterator, class _Predicate>
3550inline _LIBCPP_INLINE_VISIBILITY
3551_ForwardIterator
3552stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3553{
3554    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3555                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3556}
3557
3558// is_sorted_until
3559
3560template <class _ForwardIterator, class _Compare>
3561_ForwardIterator
3562is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3563{
3564    if (__first != __last)
3565    {
3566        _ForwardIterator __i = __first;
3567        while (++__i != __last)
3568        {
3569            if (__comp(*__i, *__first))
3570                return __i;
3571            __first = __i;
3572        }
3573    }
3574    return __last;
3575}
3576
3577template<class _ForwardIterator>
3578inline _LIBCPP_INLINE_VISIBILITY
3579_ForwardIterator
3580is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3581{
3582    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3583}
3584
3585// is_sorted
3586
3587template <class _ForwardIterator, class _Compare>
3588inline _LIBCPP_INLINE_VISIBILITY
3589bool
3590is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3591{
3592    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
3593}
3594
3595template<class _ForwardIterator>
3596inline _LIBCPP_INLINE_VISIBILITY
3597bool
3598is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3599{
3600    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3601}
3602
3603// sort
3604
3605// stable, 2-3 compares, 0-2 swaps
3606
3607template <class _Compare, class _ForwardIterator>
3608unsigned
3609__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
3610{
3611    unsigned __r = 0;
3612    if (!__c(*__y, *__x))          // if x <= y
3613    {
3614        if (!__c(*__z, *__y))      // if y <= z
3615            return __r;            // x <= y && y <= z
3616                                   // x <= y && y > z
3617        swap(*__y, *__z);          // x <= z && y < z
3618        __r = 1;
3619        if (__c(*__y, *__x))       // if x > y
3620        {
3621            swap(*__x, *__y);      // x < y && y <= z
3622            __r = 2;
3623        }
3624        return __r;                // x <= y && y < z
3625    }
3626    if (__c(*__z, *__y))           // x > y, if y > z
3627    {
3628        swap(*__x, *__z);          // x < y && y < z
3629        __r = 1;
3630        return __r;
3631    }
3632    swap(*__x, *__y);              // x > y && y <= z
3633    __r = 1;                       // x < y && x <= z
3634    if (__c(*__z, *__y))           // if y > z
3635    {
3636        swap(*__y, *__z);          // x <= y && y < z
3637        __r = 2;
3638    }
3639    return __r;
3640}                                  // x <= y && y <= z
3641
3642// stable, 3-6 compares, 0-5 swaps
3643
3644template <class _Compare, class _ForwardIterator>
3645unsigned
3646__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3647            _ForwardIterator __x4, _Compare __c)
3648{
3649    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
3650    if (__c(*__x4, *__x3))
3651    {
3652        swap(*__x3, *__x4);
3653        ++__r;
3654        if (__c(*__x3, *__x2))
3655        {
3656            swap(*__x2, *__x3);
3657            ++__r;
3658            if (__c(*__x2, *__x1))
3659            {
3660                swap(*__x1, *__x2);
3661                ++__r;
3662            }
3663        }
3664    }
3665    return __r;
3666}
3667
3668// stable, 4-10 compares, 0-9 swaps
3669
3670template <class _Compare, class _ForwardIterator>
3671unsigned
3672__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3673            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
3674{
3675    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
3676    if (__c(*__x5, *__x4))
3677    {
3678        swap(*__x4, *__x5);
3679        ++__r;
3680        if (__c(*__x4, *__x3))
3681        {
3682            swap(*__x3, *__x4);
3683            ++__r;
3684            if (__c(*__x3, *__x2))
3685            {
3686                swap(*__x2, *__x3);
3687                ++__r;
3688                if (__c(*__x2, *__x1))
3689                {
3690                    swap(*__x1, *__x2);
3691                    ++__r;
3692                }
3693            }
3694        }
3695    }
3696    return __r;
3697}
3698
3699// Assumes size > 0
3700template <class _Compare, class _BirdirectionalIterator>
3701void
3702__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3703{
3704    _BirdirectionalIterator __lm1 = __last;
3705    for (--__lm1; __first != __lm1; ++__first)
3706    {
3707        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
3708                                                        typename add_lvalue_reference<_Compare>::type>
3709                                                       (__first, __last, __comp);
3710        if (__i != __first)
3711            swap(*__first, *__i);
3712    }
3713}
3714
3715template <class _Compare, class _BirdirectionalIterator>
3716void
3717__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3718{
3719    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3720    if (__first != __last)
3721    {
3722        _BirdirectionalIterator __i = __first;
3723        for (++__i; __i != __last; ++__i)
3724        {
3725            _BirdirectionalIterator __j = __i;
3726            value_type __t(_VSTD::move(*__j));
3727            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
3728                *__j = _VSTD::move(*__k);
3729            *__j = _VSTD::move(__t);
3730        }
3731    }
3732}
3733
3734template <class _Compare, class _RandomAccessIterator>
3735void
3736__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3737{
3738    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3739    _RandomAccessIterator __j = __first+2;
3740    __sort3<_Compare>(__first, __first+1, __j, __comp);
3741    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3742    {
3743        if (__comp(*__i, *__j))
3744        {
3745            value_type __t(_VSTD::move(*__i));
3746            _RandomAccessIterator __k = __j;
3747            __j = __i;
3748            do
3749            {
3750                *__j = _VSTD::move(*__k);
3751                __j = __k;
3752            } while (__j != __first && __comp(__t, *--__k));
3753            *__j = _VSTD::move(__t);
3754        }
3755        __j = __i;
3756    }
3757}
3758
3759template <class _Compare, class _RandomAccessIterator>
3760bool
3761__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3762{
3763    switch (__last - __first)
3764    {
3765    case 0:
3766    case 1:
3767        return true;
3768    case 2:
3769        if (__comp(*--__last, *__first))
3770            swap(*__first, *__last);
3771        return true;
3772    case 3:
3773        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3774        return true;
3775    case 4:
3776        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3777        return true;
3778    case 5:
3779        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3780        return true;
3781    }
3782    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3783    _RandomAccessIterator __j = __first+2;
3784    __sort3<_Compare>(__first, __first+1, __j, __comp);
3785    const unsigned __limit = 8;
3786    unsigned __count = 0;
3787    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3788    {
3789        if (__comp(*__i, *__j))
3790        {
3791            value_type __t(_VSTD::move(*__i));
3792            _RandomAccessIterator __k = __j;
3793            __j = __i;
3794            do
3795            {
3796                *__j = _VSTD::move(*__k);
3797                __j = __k;
3798            } while (__j != __first && __comp(__t, *--__k));
3799            *__j = _VSTD::move(__t);
3800            if (++__count == __limit)
3801                return ++__i == __last;
3802        }
3803        __j = __i;
3804    }
3805    return true;
3806}
3807
3808template <class _Compare, class _BirdirectionalIterator>
3809void
3810__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
3811                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
3812{
3813    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3814    if (__first1 != __last1)
3815    {
3816        __destruct_n __d(0);
3817        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
3818        value_type* __last2 = __first2;
3819        ::new(__last2) value_type(_VSTD::move(*__first1));
3820        __d.__incr((value_type*)0);
3821        for (++__last2; ++__first1 != __last1; ++__last2)
3822        {
3823            value_type* __j2 = __last2;
3824            value_type* __i2 = __j2;
3825            if (__comp(*__first1, *--__i2))
3826            {
3827                ::new(__j2) value_type(_VSTD::move(*__i2));
3828                __d.__incr((value_type*)0);
3829                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
3830                    *__j2 = _VSTD::move(*__i2);
3831                *__j2 = _VSTD::move(*__first1);
3832            }
3833            else
3834            {
3835                ::new(__j2) value_type(_VSTD::move(*__first1));
3836                __d.__incr((value_type*)0);
3837            }
3838        }
3839        __h.release();
3840    }
3841}
3842
3843template <class _Compare, class _RandomAccessIterator>
3844void
3845__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3846{
3847    // _Compare is known to be a reference type
3848    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3849    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3850    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
3851                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
3852    while (true)
3853    {
3854    __restart:
3855        difference_type __len = __last - __first;
3856        switch (__len)
3857        {
3858        case 0:
3859        case 1:
3860            return;
3861        case 2:
3862            if (__comp(*--__last, *__first))
3863                swap(*__first, *__last);
3864            return;
3865        case 3:
3866            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3867            return;
3868        case 4:
3869            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3870            return;
3871        case 5:
3872            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3873            return;
3874        }
3875        if (__len <= __limit)
3876        {
3877            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
3878            return;
3879        }
3880        // __len > 5
3881        _RandomAccessIterator __m = __first;
3882        _RandomAccessIterator __lm1 = __last;
3883        --__lm1;
3884        unsigned __n_swaps;
3885        {
3886        difference_type __delta;
3887        if (__len >= 1000)
3888        {
3889            __delta = __len/2;
3890            __m += __delta;
3891            __delta /= 2;
3892            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
3893        }
3894        else
3895        {
3896            __delta = __len/2;
3897            __m += __delta;
3898            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
3899        }
3900        }
3901        // *__m is median
3902        // partition [__first, __m) < *__m and *__m <= [__m, __last)
3903        // (this inhibits tossing elements equivalent to __m around unnecessarily)
3904        _RandomAccessIterator __i = __first;
3905        _RandomAccessIterator __j = __lm1;
3906        // j points beyond range to be tested, *__m is known to be <= *__lm1
3907        // The search going up is known to be guarded but the search coming down isn't.
3908        // Prime the downward search with a guard.
3909        if (!__comp(*__i, *__m))  // if *__first == *__m
3910        {
3911            // *__first == *__m, *__first doesn't go in first part
3912            // manually guard downward moving __j against __i
3913            while (true)
3914            {
3915                if (__i == --__j)
3916                {
3917                    // *__first == *__m, *__m <= all other elements
3918                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
3919                    ++__i;  // __first + 1
3920                    __j = __last;
3921                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
3922                    {
3923                        while (true)
3924                        {
3925                            if (__i == __j)
3926                                return;  // [__first, __last) all equivalent elements
3927                            if (__comp(*__first, *__i))
3928                            {
3929                                swap(*__i, *__j);
3930                                ++__n_swaps;
3931                                ++__i;
3932                                break;
3933                            }
3934                            ++__i;
3935                        }
3936                    }
3937                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
3938                    if (__i == __j)
3939                        return;
3940                    while (true)
3941                    {
3942                        while (!__comp(*__first, *__i))
3943                            ++__i;
3944                        while (__comp(*__first, *--__j))
3945                            ;
3946                        if (__i >= __j)
3947                            break;
3948                        swap(*__i, *__j);
3949                        ++__n_swaps;
3950                        ++__i;
3951                    }
3952                    // [__first, __i) == *__first and *__first < [__i, __last)
3953                    // The first part is sorted, sort the secod part
3954                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
3955                    __first = __i;
3956                    goto __restart;
3957                }
3958                if (__comp(*__j, *__m))
3959                {
3960                    swap(*__i, *__j);
3961                    ++__n_swaps;
3962                    break;  // found guard for downward moving __j, now use unguarded partition
3963                }
3964            }
3965        }
3966        // It is known that *__i < *__m
3967        ++__i;
3968        // j points beyond range to be tested, *__m is known to be <= *__lm1
3969        // if not yet partitioned...
3970        if (__i < __j)
3971        {
3972            // known that *(__i - 1) < *__m
3973            // known that __i <= __m
3974            while (true)
3975            {
3976                // __m still guards upward moving __i
3977                while (__comp(*__i, *__m))
3978                    ++__i;
3979                // It is now known that a guard exists for downward moving __j
3980                while (!__comp(*--__j, *__m))
3981                    ;
3982                if (__i > __j)
3983                    break;
3984                swap(*__i, *__j);
3985                ++__n_swaps;
3986                // It is known that __m != __j
3987                // If __m just moved, follow it
3988                if (__m == __i)
3989                    __m = __j;
3990                ++__i;
3991            }
3992        }
3993        // [__first, __i) < *__m and *__m <= [__i, __last)
3994        if (__i != __m && __comp(*__m, *__i))
3995        {
3996            swap(*__i, *__m);
3997            ++__n_swaps;
3998        }
3999        // [__first, __i) < *__i and *__i <= [__i+1, __last)
4000        // If we were given a perfect partition, see if insertion sort is quick...
4001        if (__n_swaps == 0)
4002        {
4003            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
4004            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
4005            {
4006                if (__fs)
4007                    return;
4008                __last = __i;
4009                continue;
4010            }
4011            else
4012            {
4013                if (__fs)
4014                {
4015                    __first = ++__i;
4016                    continue;
4017                }
4018            }
4019        }
4020        // sort smaller range with recursive call and larger with tail recursion elimination
4021        if (__i - __first < __last - __i)
4022        {
4023            _VSTD::__sort<_Compare>(__first, __i, __comp);
4024            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4025            __first = ++__i;
4026        }
4027        else
4028        {
4029            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4030            // _VSTD::__sort<_Compare>(__first, __i, __comp);
4031            __last = __i;
4032        }
4033    }
4034}
4035
4036// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
4037template <class _RandomAccessIterator, class _Compare>
4038inline _LIBCPP_INLINE_VISIBILITY
4039void
4040sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4041{
4042#ifdef _LIBCPP_DEBUG
4043    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4044    __debug_less<_Compare> __c(__comp);
4045    __sort<_Comp_ref>(__first, __last, __c);
4046#else  // _LIBCPP_DEBUG
4047    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4048    __sort<_Comp_ref>(__first, __last, __comp);
4049#endif  // _LIBCPP_DEBUG
4050}
4051
4052template <class _RandomAccessIterator>
4053inline _LIBCPP_INLINE_VISIBILITY
4054void
4055sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4056{
4057    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4058}
4059
4060template <class _Tp>
4061inline _LIBCPP_INLINE_VISIBILITY
4062void
4063sort(_Tp** __first, _Tp** __last)
4064{
4065    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
4066}
4067
4068template <class _Tp>
4069inline _LIBCPP_INLINE_VISIBILITY
4070void
4071sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
4072{
4073    _VSTD::sort(__first.base(), __last.base());
4074}
4075
4076template <class _Tp, class _Compare>
4077inline _LIBCPP_INLINE_VISIBILITY
4078void
4079sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
4080{
4081    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4082    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
4083}
4084
4085#ifdef _LIBCPP_MSVC
4086#pragma warning( push )
4087#pragma warning( disable: 4231)
4088#endif // _LIBCPP_MSVC
4089_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
4090_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4091_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4092_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4093_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
4094_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4095_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
4096_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4097_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
4098_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4099_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4100_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4101_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
4102_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
4103_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4104
4105_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
4106_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4107_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4108_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4109_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
4110_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4111_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
4112_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4113_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
4114_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4115_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4116_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4117_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
4118_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
4119_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4120
4121_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&))
4122#ifdef _LIBCPP_MSVC
4123#pragma warning( pop )
4124#endif  // _LIBCPP_MSVC
4125
4126// lower_bound
4127
4128template <class _Compare, class _ForwardIterator, class _Tp>
4129_ForwardIterator
4130__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4131{
4132    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4133    difference_type __len = _VSTD::distance(__first, __last);
4134    while (__len != 0)
4135    {
4136        difference_type __l2 = __len / 2;
4137        _ForwardIterator __m = __first;
4138        _VSTD::advance(__m, __l2);
4139        if (__comp(*__m, __value_))
4140        {
4141            __first = ++__m;
4142            __len -= __l2 + 1;
4143        }
4144        else
4145            __len = __l2;
4146    }
4147    return __first;
4148}
4149
4150template <class _ForwardIterator, class _Tp, class _Compare>
4151inline _LIBCPP_INLINE_VISIBILITY
4152_ForwardIterator
4153lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4154{
4155#ifdef _LIBCPP_DEBUG
4156    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4157    __debug_less<_Compare> __c(__comp);
4158    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
4159#else  // _LIBCPP_DEBUG
4160    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4161    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
4162#endif  // _LIBCPP_DEBUG
4163}
4164
4165template <class _ForwardIterator, class _Tp>
4166inline _LIBCPP_INLINE_VISIBILITY
4167_ForwardIterator
4168lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4169{
4170    return _VSTD::lower_bound(__first, __last, __value_,
4171                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4172}
4173
4174// upper_bound
4175
4176template <class _Compare, class _ForwardIterator, class _Tp>
4177_ForwardIterator
4178__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4179{
4180    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4181    difference_type __len = _VSTD::distance(__first, __last);
4182    while (__len != 0)
4183    {
4184        difference_type __l2 = __len / 2;
4185        _ForwardIterator __m = __first;
4186        _VSTD::advance(__m, __l2);
4187        if (__comp(__value_, *__m))
4188            __len = __l2;
4189        else
4190        {
4191            __first = ++__m;
4192            __len -= __l2 + 1;
4193        }
4194    }
4195    return __first;
4196}
4197
4198template <class _ForwardIterator, class _Tp, class _Compare>
4199inline _LIBCPP_INLINE_VISIBILITY
4200_ForwardIterator
4201upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4202{
4203#ifdef _LIBCPP_DEBUG
4204    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4205    __debug_less<_Compare> __c(__comp);
4206    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
4207#else  // _LIBCPP_DEBUG
4208    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4209    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
4210#endif  // _LIBCPP_DEBUG
4211}
4212
4213template <class _ForwardIterator, class _Tp>
4214inline _LIBCPP_INLINE_VISIBILITY
4215_ForwardIterator
4216upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4217{
4218    return _VSTD::upper_bound(__first, __last, __value_,
4219                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
4220}
4221
4222// equal_range
4223
4224template <class _Compare, class _ForwardIterator, class _Tp>
4225pair<_ForwardIterator, _ForwardIterator>
4226__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4227{
4228    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4229    difference_type __len = _VSTD::distance(__first, __last);
4230    while (__len != 0)
4231    {
4232        difference_type __l2 = __len / 2;
4233        _ForwardIterator __m = __first;
4234        _VSTD::advance(__m, __l2);
4235        if (__comp(*__m, __value_))
4236        {
4237            __first = ++__m;
4238            __len -= __l2 + 1;
4239        }
4240        else if (__comp(__value_, *__m))
4241        {
4242            __last = __m;
4243            __len = __l2;
4244        }
4245        else
4246        {
4247            _ForwardIterator __mp1 = __m;
4248            return pair<_ForwardIterator, _ForwardIterator>
4249                   (
4250                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
4251                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
4252                   );
4253        }
4254    }
4255    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
4256}
4257
4258template <class _ForwardIterator, class _Tp, class _Compare>
4259inline _LIBCPP_INLINE_VISIBILITY
4260pair<_ForwardIterator, _ForwardIterator>
4261equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4262{
4263#ifdef _LIBCPP_DEBUG
4264    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4265    __debug_less<_Compare> __c(__comp);
4266    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
4267#else  // _LIBCPP_DEBUG
4268    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4269    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
4270#endif  // _LIBCPP_DEBUG
4271}
4272
4273template <class _ForwardIterator, class _Tp>
4274inline _LIBCPP_INLINE_VISIBILITY
4275pair<_ForwardIterator, _ForwardIterator>
4276equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4277{
4278    return _VSTD::equal_range(__first, __last, __value_,
4279                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4280}
4281
4282// binary_search
4283
4284template <class _Compare, class _ForwardIterator, class _Tp>
4285inline _LIBCPP_INLINE_VISIBILITY
4286bool
4287__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4288{
4289    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
4290    return __first != __last && !__comp(__value_, *__first);
4291}
4292
4293template <class _ForwardIterator, class _Tp, class _Compare>
4294inline _LIBCPP_INLINE_VISIBILITY
4295bool
4296binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4297{
4298#ifdef _LIBCPP_DEBUG
4299    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4300    __debug_less<_Compare> __c(__comp);
4301    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
4302#else  // _LIBCPP_DEBUG
4303    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4304    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
4305#endif  // _LIBCPP_DEBUG
4306}
4307
4308template <class _ForwardIterator, class _Tp>
4309inline _LIBCPP_INLINE_VISIBILITY
4310bool
4311binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4312{
4313    return _VSTD::binary_search(__first, __last, __value_,
4314                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4315}
4316
4317// merge
4318
4319template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4320_OutputIterator
4321__merge(_InputIterator1 __first1, _InputIterator1 __last1,
4322        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4323{
4324    for (; __first1 != __last1; ++__result)
4325    {
4326        if (__first2 == __last2)
4327            return _VSTD::copy(__first1, __last1, __result);
4328        if (__comp(*__first2, *__first1))
4329        {
4330            *__result = *__first2;
4331            ++__first2;
4332        }
4333        else
4334        {
4335            *__result = *__first1;
4336            ++__first1;
4337        }
4338    }
4339    return _VSTD::copy(__first2, __last2, __result);
4340}
4341
4342template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
4343inline _LIBCPP_INLINE_VISIBILITY
4344_OutputIterator
4345merge(_InputIterator1 __first1, _InputIterator1 __last1,
4346      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4347{
4348#ifdef _LIBCPP_DEBUG
4349    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4350    __debug_less<_Compare> __c(__comp);
4351    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
4352#else  // _LIBCPP_DEBUG
4353    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4354    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
4355#endif  // _LIBCPP_DEBUG
4356}
4357
4358template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
4359inline _LIBCPP_INLINE_VISIBILITY
4360_OutputIterator
4361merge(_InputIterator1 __first1, _InputIterator1 __last1,
4362      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
4363{
4364    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
4365    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
4366    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
4367}
4368
4369// inplace_merge
4370
4371template <class _Compare, class _BidirectionalIterator>
4372void
4373__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4374                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4375                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4376                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
4377{
4378    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4379    __destruct_n __d(0);
4380    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4381    if (__len1 <= __len2)
4382    {
4383        value_type* __p = __buff;
4384        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4385            ::new(__p) value_type(_VSTD::move(*__i));
4386        __merge<_Compare>(move_iterator<value_type*>(__buff),
4387                          move_iterator<value_type*>(__p),
4388                          move_iterator<_BidirectionalIterator>(__middle),
4389                          move_iterator<_BidirectionalIterator>(__last),
4390                          __first, __comp);
4391    }
4392    else
4393    {
4394        value_type* __p = __buff;
4395        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4396            ::new(__p) value_type(_VSTD::move(*__i));
4397        typedef reverse_iterator<_BidirectionalIterator> _RBi;
4398        typedef reverse_iterator<value_type*> _Rv;
4399        __merge(move_iterator<_RBi>(_RBi(__middle)), move_iterator<_RBi>(_RBi(__first)),
4400                move_iterator<_Rv>(_Rv(__p)), move_iterator<_Rv>(_Rv(__buff)),
4401                _RBi(__last), __negate<_Compare>(__comp));
4402    }
4403}
4404
4405template <class _Compare, class _BidirectionalIterator>
4406void
4407__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4408                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4409                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4410                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
4411{
4412    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4413    while (true)
4414    {
4415        // if __middle == __last, we're done
4416        if (__len2 == 0)
4417            return;
4418        if (__len1 <= __buff_size || __len2 <= __buff_size)
4419            return __buffered_inplace_merge<_Compare>
4420                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
4421        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
4422        for (; true; ++__first, (void) --__len1)
4423        {
4424            if (__len1 == 0)
4425                return;
4426            if (__comp(*__middle, *__first))
4427                break;
4428        }
4429        // __first < __middle < __last
4430        // *__first > *__middle
4431        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
4432        //     all elements in:
4433        //         [__first, __m1)  <= [__middle, __m2)
4434        //         [__middle, __m2) <  [__m1, __middle)
4435        //         [__m1, __middle) <= [__m2, __last)
4436        //     and __m1 or __m2 is in the middle of its range
4437        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
4438        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
4439        difference_type __len11;      // distance(__first, __m1)
4440        difference_type __len21;      // distance(__middle, __m2)
4441        // binary search smaller range
4442        if (__len1 < __len2)
4443        {   // __len >= 1, __len2 >= 2
4444            __len21 = __len2 / 2;
4445            __m2 = __middle;
4446            _VSTD::advance(__m2, __len21);
4447            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
4448            __len11 = _VSTD::distance(__first, __m1);
4449        }
4450        else
4451        {
4452            if (__len1 == 1)
4453            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
4454                // It is known *__first > *__middle
4455                swap(*__first, *__middle);
4456                return;
4457            }
4458            // __len1 >= 2, __len2 >= 1
4459            __len11 = __len1 / 2;
4460            __m1 = __first;
4461            _VSTD::advance(__m1, __len11);
4462            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
4463            __len21 = _VSTD::distance(__middle, __m2);
4464        }
4465        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
4466        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
4467        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
4468        // swap middle two partitions
4469        __middle = _VSTD::rotate(__m1, __middle, __m2);
4470        // __len12 and __len21 now have swapped meanings
4471        // merge smaller range with recurisve call and larger with tail recursion elimination
4472        if (__len11 + __len21 < __len12 + __len22)
4473        {
4474            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4475//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4476            __first = __middle;
4477            __middle = __m2;
4478            __len1 = __len12;
4479            __len2 = __len22;
4480        }
4481        else
4482        {
4483            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4484//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4485            __last = __middle;
4486            __middle = __m1;
4487            __len1 = __len11;
4488            __len2 = __len21;
4489        }
4490    }
4491}
4492
4493template <class _BidirectionalIterator, class _Compare>
4494inline _LIBCPP_INLINE_VISIBILITY
4495void
4496inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4497              _Compare __comp)
4498{
4499    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4500    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4501    difference_type __len1 = _VSTD::distance(__first, __middle);
4502    difference_type __len2 = _VSTD::distance(__middle, __last);
4503    difference_type __buf_size = _VSTD::min(__len1, __len2);
4504    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
4505    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
4506
4507#ifdef _LIBCPP_DEBUG
4508    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4509    __debug_less<_Compare> __c(__comp);
4510    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
4511                                            __buf.first, __buf.second);
4512#else  // _LIBCPP_DEBUG
4513    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4514    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
4515                                            __buf.first, __buf.second);
4516#endif  // _LIBCPP_DEBUG
4517}
4518
4519template <class _BidirectionalIterator>
4520inline _LIBCPP_INLINE_VISIBILITY
4521void
4522inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
4523{
4524    _VSTD::inplace_merge(__first, __middle, __last,
4525                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
4526}
4527
4528// stable_sort
4529
4530template <class _Compare, class _InputIterator1, class _InputIterator2>
4531void
4532__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
4533        _InputIterator2 __first2, _InputIterator2 __last2,
4534        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
4535{
4536    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
4537    __destruct_n __d(0);
4538    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
4539    for (; true; ++__result)
4540    {
4541        if (__first1 == __last1)
4542        {
4543            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
4544                ::new (__result) value_type(_VSTD::move(*__first2));
4545            __h.release();
4546            return;
4547        }
4548        if (__first2 == __last2)
4549        {
4550            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
4551                ::new (__result) value_type(_VSTD::move(*__first1));
4552            __h.release();
4553            return;
4554        }
4555        if (__comp(*__first2, *__first1))
4556        {
4557            ::new (__result) value_type(_VSTD::move(*__first2));
4558            __d.__incr((value_type*)0);
4559            ++__first2;
4560        }
4561        else
4562        {
4563            ::new (__result) value_type(_VSTD::move(*__first1));
4564            __d.__incr((value_type*)0);
4565            ++__first1;
4566        }
4567    }
4568}
4569
4570template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4571void
4572__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
4573        _InputIterator2 __first2, _InputIterator2 __last2,
4574        _OutputIterator __result, _Compare __comp)
4575{
4576    for (; __first1 != __last1; ++__result)
4577    {
4578        if (__first2 == __last2)
4579        {
4580            for (; __first1 != __last1; ++__first1, ++__result)
4581                *__result = _VSTD::move(*__first1);
4582            return;
4583        }
4584        if (__comp(*__first2, *__first1))
4585        {
4586            *__result = _VSTD::move(*__first2);
4587            ++__first2;
4588        }
4589        else
4590        {
4591            *__result = _VSTD::move(*__first1);
4592            ++__first1;
4593        }
4594    }
4595    for (; __first2 != __last2; ++__first2, ++__result)
4596        *__result = _VSTD::move(*__first2);
4597}
4598
4599template <class _Compare, class _RandomAccessIterator>
4600void
4601__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4602              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4603              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
4604
4605template <class _Compare, class _RandomAccessIterator>
4606void
4607__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
4608                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4609                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
4610{
4611    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4612    switch (__len)
4613    {
4614    case 0:
4615        return;
4616    case 1:
4617        ::new(__first2) value_type(_VSTD::move(*__first1));
4618        return;
4619    case 2:
4620       __destruct_n __d(0);
4621        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
4622         if (__comp(*--__last1, *__first1))
4623        {
4624            ::new(__first2) value_type(_VSTD::move(*__last1));
4625            __d.__incr((value_type*)0);
4626            ++__first2;
4627            ::new(__first2) value_type(_VSTD::move(*__first1));
4628        }
4629        else
4630        {
4631            ::new(__first2) value_type(_VSTD::move(*__first1));
4632            __d.__incr((value_type*)0);
4633            ++__first2;
4634            ::new(__first2) value_type(_VSTD::move(*__last1));
4635        }
4636        __h2.release();
4637        return;
4638    }
4639    if (__len <= 8)
4640    {
4641        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
4642        return;
4643    }
4644    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4645    _RandomAccessIterator __m = __first1 + __l2;
4646    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
4647    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
4648    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
4649}
4650
4651template <class _Tp>
4652struct __stable_sort_switch
4653{
4654    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
4655};
4656
4657template <class _Compare, class _RandomAccessIterator>
4658void
4659__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4660              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4661              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
4662{
4663    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4664    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4665    switch (__len)
4666    {
4667    case 0:
4668    case 1:
4669        return;
4670    case 2:
4671        if (__comp(*--__last, *__first))
4672            swap(*__first, *__last);
4673        return;
4674    }
4675    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4676    {
4677        __insertion_sort<_Compare>(__first, __last, __comp);
4678        return;
4679    }
4680    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4681    _RandomAccessIterator __m = __first + __l2;
4682    if (__len <= __buff_size)
4683    {
4684        __destruct_n __d(0);
4685        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4686        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
4687        __d.__set(__l2, (value_type*)0);
4688        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
4689        __d.__set(__len, (value_type*)0);
4690        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
4691//         __merge<_Compare>(move_iterator<value_type*>(__buff),
4692//                           move_iterator<value_type*>(__buff + __l2),
4693//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
4694//                           move_iterator<_RandomAccessIterator>(__buff + __len),
4695//                           __first, __comp);
4696        return;
4697    }
4698    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
4699    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
4700    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
4701}
4702
4703template <class _RandomAccessIterator, class _Compare>
4704inline _LIBCPP_INLINE_VISIBILITY
4705void
4706stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4707{
4708    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4709    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4710    difference_type __len = __last - __first;
4711    pair<value_type*, ptrdiff_t> __buf(0, 0);
4712    unique_ptr<value_type, __return_temporary_buffer> __h;
4713    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4714    {
4715        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
4716        __h.reset(__buf.first);
4717    }
4718#ifdef _LIBCPP_DEBUG
4719    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4720    __debug_less<_Compare> __c(__comp);
4721    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
4722#else  // _LIBCPP_DEBUG
4723    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4724    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
4725#endif  // _LIBCPP_DEBUG
4726}
4727
4728template <class _RandomAccessIterator>
4729inline _LIBCPP_INLINE_VISIBILITY
4730void
4731stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4732{
4733    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4734}
4735
4736// is_heap_until
4737
4738template <class _RandomAccessIterator, class _Compare>
4739_RandomAccessIterator
4740is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4741{
4742    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4743    difference_type __len = __last - __first;
4744    difference_type __p = 0;
4745    difference_type __c = 1;
4746    _RandomAccessIterator __pp = __first;
4747    while (__c < __len)
4748    {
4749        _RandomAccessIterator __cp = __first + __c;
4750        if (__comp(*__pp, *__cp))
4751            return __cp;
4752        ++__c;
4753        ++__cp;
4754        if (__c == __len)
4755            return __last;
4756        if (__comp(*__pp, *__cp))
4757            return __cp;
4758        ++__p;
4759        ++__pp;
4760        __c = 2 * __p + 1;
4761    }
4762    return __last;
4763}
4764
4765template<class _RandomAccessIterator>
4766inline _LIBCPP_INLINE_VISIBILITY
4767_RandomAccessIterator
4768is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
4769{
4770    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4771}
4772
4773// is_heap
4774
4775template <class _RandomAccessIterator, class _Compare>
4776inline _LIBCPP_INLINE_VISIBILITY
4777bool
4778is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4779{
4780    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
4781}
4782
4783template<class _RandomAccessIterator>
4784inline _LIBCPP_INLINE_VISIBILITY
4785bool
4786is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4787{
4788    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4789}
4790
4791// push_heap
4792
4793template <class _Compare, class _RandomAccessIterator>
4794void
4795__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4796          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4797{
4798    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4799    if (__len > 1)
4800    {
4801        __len = (__len - 2) / 2;
4802        _RandomAccessIterator __ptr = __first + __len;
4803        if (__comp(*__ptr, *--__last))
4804        {
4805            value_type __t(_VSTD::move(*__last));
4806            do
4807            {
4808                *__last = _VSTD::move(*__ptr);
4809                __last = __ptr;
4810                if (__len == 0)
4811                    break;
4812                __len = (__len - 1) / 2;
4813                __ptr = __first + __len;
4814            } while (__comp(*__ptr, __t));
4815            *__last = _VSTD::move(__t);
4816        }
4817    }
4818}
4819
4820template <class _RandomAccessIterator, class _Compare>
4821inline _LIBCPP_INLINE_VISIBILITY
4822void
4823push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4824{
4825#ifdef _LIBCPP_DEBUG
4826    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4827    __debug_less<_Compare> __c(__comp);
4828    __sift_up<_Comp_ref>(__first, __last, __c, __last - __first);
4829#else  // _LIBCPP_DEBUG
4830    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4831    __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
4832#endif  // _LIBCPP_DEBUG
4833}
4834
4835template <class _RandomAccessIterator>
4836inline _LIBCPP_INLINE_VISIBILITY
4837void
4838push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4839{
4840    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4841}
4842
4843// pop_heap
4844
4845template <class _Compare, class _RandomAccessIterator>
4846void
4847__sift_down(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4848            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4849            _RandomAccessIterator __start)
4850{
4851    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4852    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4853    // left-child of __start is at 2 * __start + 1
4854    // right-child of __start is at 2 * __start + 2
4855    difference_type __child = __start - __first;
4856
4857    if (__len < 2 || (__len - 2) / 2 < __child)
4858        return;
4859
4860    __child = 2 * __child + 1;
4861    _RandomAccessIterator __child_i = __first + __child;
4862
4863    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4864        // right-child exists and is greater than left-child
4865        ++__child_i;
4866        ++__child;
4867    }
4868
4869    // check if we are in heap-order
4870    if (__comp(*__child_i, *__start))
4871        // we are, __start is larger than it's largest child
4872        return;
4873
4874    value_type __top(_VSTD::move(*__start));
4875    do
4876    {
4877        // we are not in heap-order, swap the parent with it's largest child
4878        *__start = _VSTD::move(*__child_i);
4879        __start = __child_i;
4880
4881        if ((__len - 2) / 2 < __child)
4882            break;
4883
4884        // recompute the child based off of the updated parent
4885        __child = 2 * __child + 1;
4886        __child_i = __first + __child;
4887
4888        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4889            // right-child exists and is greater than left-child
4890            ++__child_i;
4891            ++__child;
4892        }
4893
4894        // check if we are in heap-order
4895    } while (!__comp(*__child_i, __top));
4896    *__start = _VSTD::move(__top);
4897}
4898
4899template <class _Compare, class _RandomAccessIterator>
4900inline _LIBCPP_INLINE_VISIBILITY
4901void
4902__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4903           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4904{
4905    if (__len > 1)
4906    {
4907        swap(*__first, *--__last);
4908        __sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
4909    }
4910}
4911
4912template <class _RandomAccessIterator, class _Compare>
4913inline _LIBCPP_INLINE_VISIBILITY
4914void
4915pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4916{
4917#ifdef _LIBCPP_DEBUG
4918    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4919    __debug_less<_Compare> __c(__comp);
4920    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
4921#else  // _LIBCPP_DEBUG
4922    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4923    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
4924#endif  // _LIBCPP_DEBUG
4925}
4926
4927template <class _RandomAccessIterator>
4928inline _LIBCPP_INLINE_VISIBILITY
4929void
4930pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4931{
4932    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4933}
4934
4935// make_heap
4936
4937template <class _Compare, class _RandomAccessIterator>
4938void
4939__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4940{
4941    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4942    difference_type __n = __last - __first;
4943    if (__n > 1)
4944    {
4945        // start from the first parent, there is no need to consider children
4946        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
4947        {
4948            __sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
4949        }
4950    }
4951}
4952
4953template <class _RandomAccessIterator, class _Compare>
4954inline _LIBCPP_INLINE_VISIBILITY
4955void
4956make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4957{
4958#ifdef _LIBCPP_DEBUG
4959    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4960    __debug_less<_Compare> __c(__comp);
4961    __make_heap<_Comp_ref>(__first, __last, __c);
4962#else  // _LIBCPP_DEBUG
4963    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4964    __make_heap<_Comp_ref>(__first, __last, __comp);
4965#endif  // _LIBCPP_DEBUG
4966}
4967
4968template <class _RandomAccessIterator>
4969inline _LIBCPP_INLINE_VISIBILITY
4970void
4971make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4972{
4973    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4974}
4975
4976// sort_heap
4977
4978template <class _Compare, class _RandomAccessIterator>
4979void
4980__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4981{
4982    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4983    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
4984        __pop_heap<_Compare>(__first, __last, __comp, __n);
4985}
4986
4987template <class _RandomAccessIterator, class _Compare>
4988inline _LIBCPP_INLINE_VISIBILITY
4989void
4990sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4991{
4992#ifdef _LIBCPP_DEBUG
4993    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4994    __debug_less<_Compare> __c(__comp);
4995    __sort_heap<_Comp_ref>(__first, __last, __c);
4996#else  // _LIBCPP_DEBUG
4997    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4998    __sort_heap<_Comp_ref>(__first, __last, __comp);
4999#endif  // _LIBCPP_DEBUG
5000}
5001
5002template <class _RandomAccessIterator>
5003inline _LIBCPP_INLINE_VISIBILITY
5004void
5005sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5006{
5007    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5008}
5009
5010// partial_sort
5011
5012template <class _Compare, class _RandomAccessIterator>
5013void
5014__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5015             _Compare __comp)
5016{
5017    __make_heap<_Compare>(__first, __middle, __comp);
5018    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
5019    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
5020    {
5021        if (__comp(*__i, *__first))
5022        {
5023            swap(*__i, *__first);
5024            __sift_down<_Compare>(__first, __middle, __comp, __len, __first);
5025        }
5026    }
5027    __sort_heap<_Compare>(__first, __middle, __comp);
5028}
5029
5030template <class _RandomAccessIterator, class _Compare>
5031inline _LIBCPP_INLINE_VISIBILITY
5032void
5033partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5034             _Compare __comp)
5035{
5036#ifdef _LIBCPP_DEBUG
5037    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5038    __debug_less<_Compare> __c(__comp);
5039    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
5040#else  // _LIBCPP_DEBUG
5041    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5042    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
5043#endif  // _LIBCPP_DEBUG
5044}
5045
5046template <class _RandomAccessIterator>
5047inline _LIBCPP_INLINE_VISIBILITY
5048void
5049partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
5050{
5051    _VSTD::partial_sort(__first, __middle, __last,
5052                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5053}
5054
5055// partial_sort_copy
5056
5057template <class _Compare, class _InputIterator, class _RandomAccessIterator>
5058_RandomAccessIterator
5059__partial_sort_copy(_InputIterator __first, _InputIterator __last,
5060                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5061{
5062    _RandomAccessIterator __r = __result_first;
5063    if (__r != __result_last)
5064    {
5065        for (; __first != __last && __r != __result_last; (void) ++__first, ++__r)
5066            *__r = *__first;
5067        __make_heap<_Compare>(__result_first, __r, __comp);
5068        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
5069        for (; __first != __last; ++__first)
5070            if (__comp(*__first, *__result_first))
5071            {
5072                *__result_first = *__first;
5073                __sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
5074            }
5075        __sort_heap<_Compare>(__result_first, __r, __comp);
5076    }
5077    return __r;
5078}
5079
5080template <class _InputIterator, class _RandomAccessIterator, class _Compare>
5081inline _LIBCPP_INLINE_VISIBILITY
5082_RandomAccessIterator
5083partial_sort_copy(_InputIterator __first, _InputIterator __last,
5084                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5085{
5086#ifdef _LIBCPP_DEBUG
5087    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5088    __debug_less<_Compare> __c(__comp);
5089    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
5090#else  // _LIBCPP_DEBUG
5091    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5092    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
5093#endif  // _LIBCPP_DEBUG
5094}
5095
5096template <class _InputIterator, class _RandomAccessIterator>
5097inline _LIBCPP_INLINE_VISIBILITY
5098_RandomAccessIterator
5099partial_sort_copy(_InputIterator __first, _InputIterator __last,
5100                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
5101{
5102    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
5103                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5104}
5105
5106// nth_element
5107
5108template <class _Compare, class _RandomAccessIterator>
5109void
5110__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5111{
5112    // _Compare is known to be a reference type
5113    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5114    const difference_type __limit = 7;
5115    while (true)
5116    {
5117    __restart:
5118        if (__nth == __last)
5119            return;
5120        difference_type __len = __last - __first;
5121        switch (__len)
5122        {
5123        case 0:
5124        case 1:
5125            return;
5126        case 2:
5127            if (__comp(*--__last, *__first))
5128                swap(*__first, *__last);
5129            return;
5130        case 3:
5131            {
5132            _RandomAccessIterator __m = __first;
5133            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
5134            return;
5135            }
5136        }
5137        if (__len <= __limit)
5138        {
5139            __selection_sort<_Compare>(__first, __last, __comp);
5140            return;
5141        }
5142        // __len > __limit >= 3
5143        _RandomAccessIterator __m = __first + __len/2;
5144        _RandomAccessIterator __lm1 = __last;
5145        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
5146        // *__m is median
5147        // partition [__first, __m) < *__m and *__m <= [__m, __last)
5148        // (this inhibits tossing elements equivalent to __m around unnecessarily)
5149        _RandomAccessIterator __i = __first;
5150        _RandomAccessIterator __j = __lm1;
5151        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5152        // The search going up is known to be guarded but the search coming down isn't.
5153        // Prime the downward search with a guard.
5154        if (!__comp(*__i, *__m))  // if *__first == *__m
5155        {
5156            // *__first == *__m, *__first doesn't go in first part
5157            // manually guard downward moving __j against __i
5158            while (true)
5159            {
5160                if (__i == --__j)
5161                {
5162                    // *__first == *__m, *__m <= all other elements
5163                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
5164                    ++__i;  // __first + 1
5165                    __j = __last;
5166                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
5167                    {
5168                        while (true)
5169                        {
5170                            if (__i == __j)
5171                                return;  // [__first, __last) all equivalent elements
5172                            if (__comp(*__first, *__i))
5173                            {
5174                                swap(*__i, *__j);
5175                                ++__n_swaps;
5176                                ++__i;
5177                                break;
5178                            }
5179                            ++__i;
5180                        }
5181                    }
5182                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
5183                    if (__i == __j)
5184                        return;
5185                    while (true)
5186                    {
5187                        while (!__comp(*__first, *__i))
5188                            ++__i;
5189                        while (__comp(*__first, *--__j))
5190                            ;
5191                        if (__i >= __j)
5192                            break;
5193                        swap(*__i, *__j);
5194                        ++__n_swaps;
5195                        ++__i;
5196                    }
5197                    // [__first, __i) == *__first and *__first < [__i, __last)
5198                    // The first part is sorted,
5199                    if (__nth < __i)
5200                        return;
5201                    // __nth_element the secod part
5202                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
5203                    __first = __i;
5204                    goto __restart;
5205                }
5206                if (__comp(*__j, *__m))
5207                {
5208                    swap(*__i, *__j);
5209                    ++__n_swaps;
5210                    break;  // found guard for downward moving __j, now use unguarded partition
5211                }
5212            }
5213        }
5214        ++__i;
5215        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5216        // if not yet partitioned...
5217        if (__i < __j)
5218        {
5219            // known that *(__i - 1) < *__m
5220            while (true)
5221            {
5222                // __m still guards upward moving __i
5223                while (__comp(*__i, *__m))
5224                    ++__i;
5225                // It is now known that a guard exists for downward moving __j
5226                while (!__comp(*--__j, *__m))
5227                    ;
5228                if (__i >= __j)
5229                    break;
5230                swap(*__i, *__j);
5231                ++__n_swaps;
5232                // It is known that __m != __j
5233                // If __m just moved, follow it
5234                if (__m == __i)
5235                    __m = __j;
5236                ++__i;
5237            }
5238        }
5239        // [__first, __i) < *__m and *__m <= [__i, __last)
5240        if (__i != __m && __comp(*__m, *__i))
5241        {
5242            swap(*__i, *__m);
5243            ++__n_swaps;
5244        }
5245        // [__first, __i) < *__i and *__i <= [__i+1, __last)
5246        if (__nth == __i)
5247            return;
5248        if (__n_swaps == 0)
5249        {
5250            // We were given a perfectly partitioned sequence.  Coincidence?
5251            if (__nth < __i)
5252            {
5253                // Check for [__first, __i) already sorted
5254                __j = __m = __first;
5255                while (++__j != __i)
5256                {
5257                    if (__comp(*__j, *__m))
5258                        // not yet sorted, so sort
5259                        goto not_sorted;
5260                    __m = __j;
5261                }
5262                // [__first, __i) sorted
5263                return;
5264            }
5265            else
5266            {
5267                // Check for [__i, __last) already sorted
5268                __j = __m = __i;
5269                while (++__j != __last)
5270                {
5271                    if (__comp(*__j, *__m))
5272                        // not yet sorted, so sort
5273                        goto not_sorted;
5274                    __m = __j;
5275                }
5276                // [__i, __last) sorted
5277                return;
5278            }
5279        }
5280not_sorted:
5281        // __nth_element on range containing __nth
5282        if (__nth < __i)
5283        {
5284            // __nth_element<_Compare>(__first, __nth, __i, __comp);
5285            __last = __i;
5286        }
5287        else
5288        {
5289            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
5290            __first = ++__i;
5291        }
5292    }
5293}
5294
5295template <class _RandomAccessIterator, class _Compare>
5296inline _LIBCPP_INLINE_VISIBILITY
5297void
5298nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5299{
5300#ifdef _LIBCPP_DEBUG
5301    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5302    __debug_less<_Compare> __c(__comp);
5303    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
5304#else  // _LIBCPP_DEBUG
5305    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5306    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
5307#endif  // _LIBCPP_DEBUG
5308}
5309
5310template <class _RandomAccessIterator>
5311inline _LIBCPP_INLINE_VISIBILITY
5312void
5313nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
5314{
5315    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5316}
5317
5318// includes
5319
5320template <class _Compare, class _InputIterator1, class _InputIterator2>
5321bool
5322__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5323           _Compare __comp)
5324{
5325    for (; __first2 != __last2; ++__first1)
5326    {
5327        if (__first1 == __last1 || __comp(*__first2, *__first1))
5328            return false;
5329        if (!__comp(*__first1, *__first2))
5330            ++__first2;
5331    }
5332    return true;
5333}
5334
5335template <class _InputIterator1, class _InputIterator2, class _Compare>
5336inline _LIBCPP_INLINE_VISIBILITY
5337bool
5338includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5339         _Compare __comp)
5340{
5341#ifdef _LIBCPP_DEBUG
5342    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5343    __debug_less<_Compare> __c(__comp);
5344    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5345#else  // _LIBCPP_DEBUG
5346    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5347    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5348#endif  // _LIBCPP_DEBUG
5349}
5350
5351template <class _InputIterator1, class _InputIterator2>
5352inline _LIBCPP_INLINE_VISIBILITY
5353bool
5354includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
5355{
5356    return _VSTD::includes(__first1, __last1, __first2, __last2,
5357                          __less<typename iterator_traits<_InputIterator1>::value_type,
5358                                 typename iterator_traits<_InputIterator2>::value_type>());
5359}
5360
5361// set_union
5362
5363template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5364_OutputIterator
5365__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5366            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5367{
5368    for (; __first1 != __last1; ++__result)
5369    {
5370        if (__first2 == __last2)
5371            return _VSTD::copy(__first1, __last1, __result);
5372        if (__comp(*__first2, *__first1))
5373        {
5374            *__result = *__first2;
5375            ++__first2;
5376        }
5377        else
5378        {
5379            *__result = *__first1;
5380            if (!__comp(*__first1, *__first2))
5381                ++__first2;
5382            ++__first1;
5383        }
5384    }
5385    return _VSTD::copy(__first2, __last2, __result);
5386}
5387
5388template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5389inline _LIBCPP_INLINE_VISIBILITY
5390_OutputIterator
5391set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5392          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5393{
5394#ifdef _LIBCPP_DEBUG
5395    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5396    __debug_less<_Compare> __c(__comp);
5397    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5398#else  // _LIBCPP_DEBUG
5399    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5400    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5401#endif  // _LIBCPP_DEBUG
5402}
5403
5404template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5405inline _LIBCPP_INLINE_VISIBILITY
5406_OutputIterator
5407set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5408          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5409{
5410    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
5411                          __less<typename iterator_traits<_InputIterator1>::value_type,
5412                                 typename iterator_traits<_InputIterator2>::value_type>());
5413}
5414
5415// set_intersection
5416
5417template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5418_OutputIterator
5419__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5420                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5421{
5422    while (__first1 != __last1 && __first2 != __last2)
5423    {
5424        if (__comp(*__first1, *__first2))
5425            ++__first1;
5426        else
5427        {
5428            if (!__comp(*__first2, *__first1))
5429            {
5430                *__result = *__first1;
5431                ++__result;
5432                ++__first1;
5433            }
5434            ++__first2;
5435        }
5436    }
5437    return __result;
5438}
5439
5440template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5441inline _LIBCPP_INLINE_VISIBILITY
5442_OutputIterator
5443set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5444                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5445{
5446#ifdef _LIBCPP_DEBUG
5447    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5448    __debug_less<_Compare> __c(__comp);
5449    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5450#else  // _LIBCPP_DEBUG
5451    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5452    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5453#endif  // _LIBCPP_DEBUG
5454}
5455
5456template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5457inline _LIBCPP_INLINE_VISIBILITY
5458_OutputIterator
5459set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5460                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5461{
5462    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
5463                                  __less<typename iterator_traits<_InputIterator1>::value_type,
5464                                         typename iterator_traits<_InputIterator2>::value_type>());
5465}
5466
5467// set_difference
5468
5469template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5470_OutputIterator
5471__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5472                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5473{
5474    while (__first1 != __last1)
5475    {
5476        if (__first2 == __last2)
5477            return _VSTD::copy(__first1, __last1, __result);
5478        if (__comp(*__first1, *__first2))
5479        {
5480            *__result = *__first1;
5481            ++__result;
5482            ++__first1;
5483        }
5484        else
5485        {
5486            if (!__comp(*__first2, *__first1))
5487                ++__first1;
5488            ++__first2;
5489        }
5490    }
5491    return __result;
5492}
5493
5494template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5495inline _LIBCPP_INLINE_VISIBILITY
5496_OutputIterator
5497set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5498               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5499{
5500#ifdef _LIBCPP_DEBUG
5501    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5502    __debug_less<_Compare> __c(__comp);
5503    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5504#else  // _LIBCPP_DEBUG
5505    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5506    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5507#endif  // _LIBCPP_DEBUG
5508}
5509
5510template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5511inline _LIBCPP_INLINE_VISIBILITY
5512_OutputIterator
5513set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5514               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5515{
5516    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
5517                                __less<typename iterator_traits<_InputIterator1>::value_type,
5518                                       typename iterator_traits<_InputIterator2>::value_type>());
5519}
5520
5521// set_symmetric_difference
5522
5523template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5524_OutputIterator
5525__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5526                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5527{
5528    while (__first1 != __last1)
5529    {
5530        if (__first2 == __last2)
5531            return _VSTD::copy(__first1, __last1, __result);
5532        if (__comp(*__first1, *__first2))
5533        {
5534            *__result = *__first1;
5535            ++__result;
5536            ++__first1;
5537        }
5538        else
5539        {
5540            if (__comp(*__first2, *__first1))
5541            {
5542                *__result = *__first2;
5543                ++__result;
5544            }
5545            else
5546                ++__first1;
5547            ++__first2;
5548        }
5549    }
5550    return _VSTD::copy(__first2, __last2, __result);
5551}
5552
5553template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5554inline _LIBCPP_INLINE_VISIBILITY
5555_OutputIterator
5556set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5557                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5558{
5559#ifdef _LIBCPP_DEBUG
5560    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5561    __debug_less<_Compare> __c(__comp);
5562    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5563#else  // _LIBCPP_DEBUG
5564    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5565    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5566#endif  // _LIBCPP_DEBUG
5567}
5568
5569template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5570inline _LIBCPP_INLINE_VISIBILITY
5571_OutputIterator
5572set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5573                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5574{
5575    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
5576                                          __less<typename iterator_traits<_InputIterator1>::value_type,
5577                                                 typename iterator_traits<_InputIterator2>::value_type>());
5578}
5579
5580// lexicographical_compare
5581
5582template <class _Compare, class _InputIterator1, class _InputIterator2>
5583bool
5584__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5585                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5586{
5587    for (; __first2 != __last2; ++__first1, (void) ++__first2)
5588    {
5589        if (__first1 == __last1 || __comp(*__first1, *__first2))
5590            return true;
5591        if (__comp(*__first2, *__first1))
5592            return false;
5593    }
5594    return false;
5595}
5596
5597template <class _InputIterator1, class _InputIterator2, class _Compare>
5598inline _LIBCPP_INLINE_VISIBILITY
5599bool
5600lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5601                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5602{
5603#ifdef _LIBCPP_DEBUG
5604    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5605    __debug_less<_Compare> __c(__comp);
5606    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5607#else  // _LIBCPP_DEBUG
5608    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5609    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5610#endif  // _LIBCPP_DEBUG
5611}
5612
5613template <class _InputIterator1, class _InputIterator2>
5614inline _LIBCPP_INLINE_VISIBILITY
5615bool
5616lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5617                        _InputIterator2 __first2, _InputIterator2 __last2)
5618{
5619    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
5620                                         __less<typename iterator_traits<_InputIterator1>::value_type,
5621                                                typename iterator_traits<_InputIterator2>::value_type>());
5622}
5623
5624// next_permutation
5625
5626template <class _Compare, class _BidirectionalIterator>
5627bool
5628__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5629{
5630    _BidirectionalIterator __i = __last;
5631    if (__first == __last || __first == --__i)
5632        return false;
5633    while (true)
5634    {
5635        _BidirectionalIterator __ip1 = __i;
5636        if (__comp(*--__i, *__ip1))
5637        {
5638            _BidirectionalIterator __j = __last;
5639            while (!__comp(*__i, *--__j))
5640                ;
5641            swap(*__i, *__j);
5642            _VSTD::reverse(__ip1, __last);
5643            return true;
5644        }
5645        if (__i == __first)
5646        {
5647            _VSTD::reverse(__first, __last);
5648            return false;
5649        }
5650    }
5651}
5652
5653template <class _BidirectionalIterator, class _Compare>
5654inline _LIBCPP_INLINE_VISIBILITY
5655bool
5656next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5657{
5658#ifdef _LIBCPP_DEBUG
5659    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5660    __debug_less<_Compare> __c(__comp);
5661    return __next_permutation<_Comp_ref>(__first, __last, __c);
5662#else  // _LIBCPP_DEBUG
5663    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5664    return __next_permutation<_Comp_ref>(__first, __last, __comp);
5665#endif  // _LIBCPP_DEBUG
5666}
5667
5668template <class _BidirectionalIterator>
5669inline _LIBCPP_INLINE_VISIBILITY
5670bool
5671next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5672{
5673    return _VSTD::next_permutation(__first, __last,
5674                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5675}
5676
5677// prev_permutation
5678
5679template <class _Compare, class _BidirectionalIterator>
5680bool
5681__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5682{
5683    _BidirectionalIterator __i = __last;
5684    if (__first == __last || __first == --__i)
5685        return false;
5686    while (true)
5687    {
5688        _BidirectionalIterator __ip1 = __i;
5689        if (__comp(*__ip1, *--__i))
5690        {
5691            _BidirectionalIterator __j = __last;
5692            while (!__comp(*--__j, *__i))
5693                ;
5694            swap(*__i, *__j);
5695            _VSTD::reverse(__ip1, __last);
5696            return true;
5697        }
5698        if (__i == __first)
5699        {
5700            _VSTD::reverse(__first, __last);
5701            return false;
5702        }
5703    }
5704}
5705
5706template <class _BidirectionalIterator, class _Compare>
5707inline _LIBCPP_INLINE_VISIBILITY
5708bool
5709prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5710{
5711#ifdef _LIBCPP_DEBUG
5712    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5713    __debug_less<_Compare> __c(__comp);
5714    return __prev_permutation<_Comp_ref>(__first, __last, __c);
5715#else  // _LIBCPP_DEBUG
5716    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5717    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
5718#endif  // _LIBCPP_DEBUG
5719}
5720
5721template <class _BidirectionalIterator>
5722inline _LIBCPP_INLINE_VISIBILITY
5723bool
5724prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5725{
5726    return _VSTD::prev_permutation(__first, __last,
5727                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5728}
5729
5730template <class _Tp>
5731inline _LIBCPP_INLINE_VISIBILITY
5732typename enable_if
5733<
5734    is_integral<_Tp>::value,
5735    _Tp
5736>::type
5737__rotate_left(_Tp __t, _Tp __n = 1)
5738{
5739    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5740    __n &= __bits;
5741    return static_cast<_Tp>((__t << __n) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> (__bits - __n)));
5742}
5743
5744template <class _Tp>
5745inline _LIBCPP_INLINE_VISIBILITY
5746typename enable_if
5747<
5748    is_integral<_Tp>::value,
5749    _Tp
5750>::type
5751__rotate_right(_Tp __t, _Tp __n = 1)
5752{
5753    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5754    __n &= __bits;
5755    return static_cast<_Tp>((__t << (__bits - __n)) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> __n));
5756}
5757
5758_LIBCPP_END_NAMESPACE_STD
5759
5760#endif  // _LIBCPP_ALGORITHM
5761