思路: 简单搜索 总结: dfs 框架 1. 需要打印路径. 在 dfs 函数中假如 vector 变量, 不用 & 修饰的话就不需要 undo 2. 不需要打印路径, 可设置全局变量 ans, 在 dfs 函数中对 ans 判定, 判定的位置尽可能的多 3. 对 tree 遍历, 有两种办法, 第一种是 if(root == NULL) 第二种是 if(root->left == NULL), 我一般用第二种, 效率比较高, 但是在第二种 return 1, 第一种 return 0 4.…

Problem Link: http://oj.leetcode.com/problems/binary-tree-maximum-path-sum/ For any path P in a binary tree, there must exists a node N in P such that N is the ancestor node of all other nodes in P. We call such N as the root of P, or P roots at N. T…

Path Sum 题目链接 题目要求: 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. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 /…

112题目如下: 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. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 r…

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…

Path Sum OJ: https://oj.leetcode.com/problems/path-sum/ 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. For example: Given the below binary tree and…

LeetCode--Maximum Depth of Binary Tree Question 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. Answer /** * Definition for a binary tree…

Path Sum Total Accepted: 81706 Total Submissions: 269391 Difficulty: Easy 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. For example:Given the below…

题目来源: https://leetcode.com/problems/simplify-path/ 题意分析: 简化Unix上的绝对路径,也就是多个'/'代表一个,'..'表示返回上一级目录,‘.'代表当前目录. 题目思路: 利用栈,把非'/'和'.'push进栈,如果遇到'..'pop掉一个,否则继续push进去.最后还原成路径格式. 代码(Python): class Solution(object): def simplifyPath(self, path): """…

LeetCode:Maximum Depth of Binary Tree [问题再现] 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. [优质算法] 算法一: public class Solution { public in…