题目: Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note:A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? confused what "{1,#,2,3}&…

开一个指针数组,中序遍历这个二叉搜索树,将节点的指针依次保存在数组里, 然后寻找两处逆序的位置, 中序便利里BST得到的是升序序列 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 二叉搜索树(BST)中的两个节点不小心被交换了下. 不改变其结构的情况下恢复这个树. 笔记: 用O(n)的空间复杂度的方法很直接.你能否设计一个常量空间的解决法方案? +++++++++++++++++…

题目: Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with…

题目: Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that…

本质上是递归遍历左右后在与根节点做判断,本质上是后序遍历 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 给你一个二叉树,判断他是否是个有效的二叉查找树(BST). 假定一个BST树按照下面的内容定义: 左子树的节点的值都小于父节点. 右子树的节点的值都大于父节点. 左子树和右子树都得是合法的而二叉查找树. ++++++++++++++++++++++++++++++++++++…

题目: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 代码: class Solution { public: int numTrees(i…

题目: Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. 代码: /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {}…

题目: Given an array where elements are sorted in ascending order, convert it to a height balanced BST. 代码: /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NU…

[LeetCode]99. Recover Binary Search Tree 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/recover-binary-search-tree/description/ 题目描述: Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without chan…

Recover Binary Search Tree Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note:A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? 中序…