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 keys…

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 keys…

98. 验证二叉搜索树 题目来源:https://leetcode-cn.com/problems/validate-binary-search-tree 题目 给定一个二叉树,判断其是否是一个有效的二叉搜索树. 假设一个二叉搜索树具有如下特征: 节点的左子树只包含小于当前节点的数. 节点的右子树只包含大于当前节点的数. 所有左子树和右子树自身必须也是二叉搜索树. 示例 1: 输入: 2 / \ 1 3 输出: true 示例 2: 输入: 5 / \ 1 4 / \ 3 6 输出: false…

98. 验证二叉搜索树 给定一个二叉树,判断其是否是一个有效的二叉搜索树. 假设一个二叉搜索树具有如下特征: 节点的左子树只包含小于当前节点的数. 节点的右子树只包含大于当前节点的数. 所有左子树和右子树自身必须也是二叉搜索树. 示例 1: 输入: 2 / \ 1 3 输出: true 示例 2: 输入: 5 / \ 1 4 / \ 3 6 输出: false 解释: 输入为: [5,1,4,null,null,3,6]. 根节点的值为 5 ,但是其右子节点值为 4 . class Soluti…

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 keys…

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 keys…

题目: 给定一个二叉树,判断其是否是一个有效的二叉搜索树. 假设一个二叉搜索树具有如下特征: 节点的左子树只包含小于当前节点的数. 节点的右子树只包含大于当前节点的数. 所有左子树和右子树自身必须也是二叉搜索树. 示例 1: 输入: 2 / \ 1 3 输出: true 示例 2: 输入: 5 / \ 1 4   / \   3 6 输出: false 解释: 输入为: [5,1,4,null,null,3,6].   根节点的值为 5 ,但是其右子节点值为 4 . 解题思路: 根据二叉搜索树的…

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 keys…

/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: bool isValidBST(TreeNode* root) { vector<int> res; ;…

描述 解析 二叉搜索树,其实就是节点n的左孩子所在的树,每个节点都小于节点n. 节点n的右孩子所在的树,每个节点都大于节点n. 定义子树的最大最小值 比如:左孩子要小于父节点:左孩子n的右孩子要大于n的父节点.以此类推. 中序遍历 中序遍历时,输出的值,和前一个值比较,如果大,就失败. 代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNo…