算法分析:求树的最小最大深度时候,都有两种方法,第一种是递归思想.树最大最小深度,即为它的子树的最大最小深度+1,是动态规划的思想.还有一种方法是层序遍历树,只不过求最小深度时,找到第一个叶子节点就可以返回,该节点的深度,即为树的最小深度.求最大深度时,需要层序遍历完整棵树. public class MaximumDepthofBinaryTree { public int maxDepth(TreeNode root) { if(root == null) { return 0; } int…

104. 二叉树的最大深度 104. Maximum Depth of Binary Tree 题目描述 给定一个二叉树,找出其最大深度. 二叉树的深度为根节点到最远叶子节点的最长路径上的节点数. 说明: 叶子节点是指没有子节点的节点. LeetCode104. Maximum Depth of Binary Tree 示例: 给定二叉树 [3,9,20,null,null,15,7], 3 / \ 9 20 / \ 15 7 返回它的最大深度 3. Java 实现 class TreeNode…

258. Add Digits Digit root 数根问题 /** * @param {number} num * @return {number} */ var addDigits = function(num) { var b = (num-1) % 9 + 1 ; return b; }; //之所以num要-1再+1;是因为特殊情况下:当num是9的倍数时,0+9的数字根和0的数字根不同. 性质说明 1.任何数加9的数字根还是它本身.(特殊情况num=0)        小学学加法的…

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 leaf node. Have you met this question in a real interview? Yes Example Given a binary tree as follow:…

Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 比较左子树和右子树的深度,取小的那个返回上来,并+1. 需要注意的是如果没有左子树或右子树.那么无条件取存在的那一边子树深…

LeetCode:Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 算法1:dfs递归的求解 class Solution { public: int minDepth(T…

Same Tree 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 and the nodes have the same value. Maximum Depth of Binary Tree Given a binary tree, find i…

Minimum Depth of Binary Tree OJ: https://oj.leetcode.com/problems/minimum-depth-of-binary-tree/ Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf…

Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. BFS碰到一个叶子结点就可以了. class Solution { public: int minDepth(TreeNo…

104. Maximum Depth of Binary Tree 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 leaf node. 题目大意: 给一颗二叉树,求最大深度. 解题方法: 1.利用递归遍历二叉树. 注意事项: C++代码: /**…