11d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2011 The Guava Authors 31d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 41d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 51d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * in compliance with the License. You may obtain a copy of the License at 61d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 71d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * http://www.apache.org/licenses/LICENSE-2.0 81d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 91d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Unless required by applicable law or agreed to in writing, software distributed under the 101d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 111d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * express or implied. See the License for the specific language governing permissions and 121d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * limitations under the License. 131d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 141d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 151d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertpackage com.google.common.collect; 161d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 171d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport static com.google.common.base.Preconditions.checkNotNull; 181d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.annotations.GwtCompatible; 201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.base.Optional; 211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 221d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport java.util.NoSuchElementException; 231d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 241d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport javax.annotation.Nullable; 251d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 261d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/** 271d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * A {@code BstPath} supporting inorder traversal operations. 281d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 291d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @author Louis Wasserman 301d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 311d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert@GwtCompatible 321d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertfinal class BstInOrderPath<N extends BstNode<?, N>> extends BstPath<N, BstInOrderPath<N>> { 331d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 341d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * The factory to use to construct {@code BstInOrderPath} values. 351d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 361d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public static <N extends BstNode<?, N>> BstPathFactory<N, BstInOrderPath<N>> inOrderFactory() { 371d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return new BstPathFactory<N, BstInOrderPath<N>>() { 381d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override 391d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public BstInOrderPath<N> extension(BstInOrderPath<N> path, BstSide side) { 401d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return BstInOrderPath.extension(path, side); 411d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 421d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 431d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override 441d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public BstInOrderPath<N> initialPath(N root) { 451d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return new BstInOrderPath<N>(root, null, null); 461d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 471d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert }; 481d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 491d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 501d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private static <N extends BstNode<?, N>> BstInOrderPath<N> extension( 511d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert BstInOrderPath<N> path, BstSide side) { 521d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert checkNotNull(path); 531d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert N tip = path.getTip(); 541d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return new BstInOrderPath<N>(tip.getChild(side), side, path); 551d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 561d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 571d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private final BstSide sideExtension; 581d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private transient Optional<BstInOrderPath<N>> prevInOrder; 591d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private transient Optional<BstInOrderPath<N>> nextInOrder; 601d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 611d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private BstInOrderPath( 621d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert N tip, @Nullable BstSide sideExtension, @Nullable BstInOrderPath<N> tail) { 631d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert super(tip, tail); 641d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert this.sideExtension = sideExtension; 651d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert assert (sideExtension == null) == (tail == null); 661d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 671d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 681d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private Optional<BstInOrderPath<N>> computeNextInOrder(BstSide side) { 691d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert if (getTip().hasChild(side)) { 701d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert BstInOrderPath<N> path = extension(this, side); 711d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert BstSide otherSide = side.other(); 721d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert while (path.getTip().hasChild(otherSide)) { 731d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert path = extension(path, otherSide); 741d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 751d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return Optional.of(path); 761d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } else { 771d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert BstInOrderPath<N> current = this; 781d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert while (current.sideExtension == side) { 791d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert current = current.getPrefix(); 801d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 811d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert current = current.prefixOrNull(); 821d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return Optional.fromNullable(current); 831d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 841d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 851d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 861d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert private Optional<BstInOrderPath<N>> nextInOrder(BstSide side) { 871d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert Optional<BstInOrderPath<N>> result; 881d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert switch (side) { 891d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert case LEFT: 901d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert result = prevInOrder; 911d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return (result == null) ? prevInOrder = computeNextInOrder(side) : result; 921d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert case RIGHT: 931d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert result = nextInOrder; 941d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return (result == null) ? nextInOrder = computeNextInOrder(side) : result; 951d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert default: 961d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert throw new AssertionError(); 971d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 981d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 991d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 1001d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 1011d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Returns {@code true} if there is a next path in an in-order traversal in the given direction. 1021d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 1031d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public boolean hasNext(BstSide side) { 1041d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return nextInOrder(side).isPresent(); 1051d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 1061d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 1071d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 1081d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Returns the next path in an in-order traversal in the given direction. 1091d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 1101d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @throws NoSuchElementException if this would be the last path in an in-order traversal 1111d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 1121d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public BstInOrderPath<N> next(BstSide side) { 1131d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert if (!hasNext(side)) { 1141d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert throw new NoSuchElementException(); 1151d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 1161d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return nextInOrder(side).get(); 1171d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 1181d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 1191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 1201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Returns the direction this path went in relative to its tail path, or {@code null} if this 1211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * path has no tail. 1221d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 1231d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public BstSide getSideOfExtension() { 1241d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return sideExtension; 1251d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 1261d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert} 127