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Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST.Callingnext()will return the next... 阅读全文
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Given a binary tree, return thebottom-up level ordertraversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For exa... 阅读全文
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Given a binary tree, return thelevel ordertraversal of its nodes' values. (ie, from left to right, level by level).For example:Given binary tree{3,9,2... 阅读全文
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Invert a binary tree. 4 / \ 2 7 / \ / \1 3 6 9to 4 / \ 7 2 / \ / \9 6 3 1Trivia:This problem was inspired bythis... 阅读全文
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Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.According to thedefinition of LCA on Wikipedia: ... 阅读全文
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Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest le... 阅读全文
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Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.Fo... 阅读全文
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Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ ... 阅读全文
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Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical an... 阅读全文
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Given a binary tree, return all root-to-leaf paths.For example, given the following binary tree: 1 / \2 3 \ 5All root-to-leaf paths are:["1->2->5"... 阅读全文
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Given an array withnobjects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, wh... 阅读全文
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Sort a linked list inO(nlogn) time using constant space complexity.题目要求在常数控件内以O(nlogn)的事件复杂度来排序链表。常数空间内我没有实现，O(nlogn)的话使用归并排序就可以了吗， 下面是代码： 1 /** 2 * ... 阅读全文