正常写法 bool HasPathSum(TreeNode root, int sum) { bool ret=false; if(root==null)return false; if(root.left==null&&root.right==null) return root.val==sum; if(root.left!=null) { ret=ret|| HasPathSum(root.left,sum-root.val); } if(root.right!=null) { ret…

Path sum: four ways NOTE: This problem is a significantly more challenging version of Problem 81. In the 5 by 5 matrix below, the minimal path sum from the top left to the bottom right, by moving left, right, up, and down, is indicated in bold red an…

Path sum: three ways NOTE: This problem is a more challenging version of Problem 81. The minimal path sum in the 5 by 5 matrix below, by starting in any cell in the left column and finishing in any cell in the right column, and only moving up, down,…

Path sum: two ways In the 5 by 5 matrix below, the minimal path sum from the top left to the bottom right, by only moving to the right and down, is indicated in bold red and is equal to 2427.           131 673 234 103 18 201 96 342 965 150 630 803 74…

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 /…

题目: 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 retu…

前言   [LeetCode 题解]系列传送门:  http://www.cnblogs.com/double-win/category/573499.html   1.题目描述 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 a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 求路径的和与某一特定的值时候对等即可,简…

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 要求求出是否有一条路径…

题目链接:Path Sum II | LeetCode OJ Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2],…

题目链接:Path Sum | LeetCode OJ 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…

Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example:Given the below binary tree, 1 / \ 2 3 Return 6. 这道求二叉树的最大路径和是一道蛮有难度的题,难就难在起始位置和结束位置可以为任意位置,我当然是又不会了,于是上网看看大神们的解法,看了很多人的都没太看明白,最后发现了网友Yu's…

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 这道二叉树路径之和在之前的基础上又需要找…

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 return true…

If the depth of a tree is smaller than 5, then this tree can be represented by a list of three-digits integers. For each integer in this list: The hundreds digit represents the depth D of this node, 1 <= D <= 4. The tens digit represents the positio…

［抄题］: 给出一棵二叉树,寻找一条路径使其路径和最大,路径可以在任一节点中开始和结束(路径和为两个节点之间所在路径上的节点权值之和) ［思维问题］: 不会写分合法 ［一句话思路］: 用两次分治:root2any any2any分一次,左右再分一次. ［输入量］:空: 正常情况:特大:特小:程序里处理到的特殊情况:异常情况(不合法不合理的输入): ［画图］: 先root-any左右各一次,再用any-any. ［一刷］: left right都是resultType类型,要用到helper函数…

［抄题］: 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 retur…

Given a non-empty binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The path must contain at least one node and doe…

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 这道二叉树路径之和在之前那道题 Path…

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. Note: A leaf is a node with no children. Example: Given the below binary tree and sum = 22, 5 / \ 4 8…

Path Sum 题目 给予一个二叉树,和一个值su,寻找是否有一个从根节点到叶节点的和为su,有则返回True,没有为False.比如: 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 hasPathSum(self, root, 22) 将返回True 节点为: class TreeNode: def __init__(self, x): self.val = x self.left = None self.right = None 解题思路 class Soluti…

之所以将这三道题放在一起,是因为这三道题非常类似. 1. Minimum Path Sum 题目链接 题目要求: Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or righ…

Given a binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The path does not need to go through the root. For exampl…

题目 二叉树不超过1000个节点,且节点数值范围是 [-1000000,1000000] 的整数. 示例: root = [10,5,-3,3,2,null,11,3,-2,null,1], sum = 8 10 / \ 5 -3 / \ \ 3 2 11 / \ \ 3 -2 1 返回 3.和等于 8 的路径有: 1. 5 -> 3 2. 5 -> 2 -> 1 3. -3 -> 11 考点 1.map 2.tree 3.dfs 4.递归 5.先序遍历 思路 这道题让我们求二叉树…

You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it must go downwards (traveling only from parent nodes to…

Path Sum II Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [[5,4,11,2],[5,8,4,5]] 分析: dfs求解即可…

Binary Tree Maximum Path Sum Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example: Given the below binary tree, 1 / \ 2 3 Return 6. 递归求解. maxPathSum(root)跟maxPathSum(root.left)和maxPathSum(roo…

Path Sum II Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 这个问题需要返…

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 sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 re…

题目: Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example: Given the below binary tree, 1 / \ 2 3 Return 6. 解题思路: 最长路径和要分几种情况考虑,对于这样一个节点 cur / \ left right 设left是左子树的最长路径和,right是右子树的最长路径和,要求当前…