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 r…

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. 题解: 递归求解. 取当前点和左右边加和,当前点的值中最大的作为本层返回值.并在全局维护一个max.使用数组,因为是引用类型.所以在递归过程中可以保存结果. 代码如下:…

题目: 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 right at any point in time. 题解: 这道题跟Unique Path系列是思路一样的.具…

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 return…

在Path SUm 1中(http://www.cnblogs.com/hitkb/p/4242822.html) 我们采用栈的形式保存路径,每当找到符合的叶子节点,就将栈内元素输出.注意存在多条路径的情况. public List<List<Integer>> pathSum(TreeNode root, int sum) { List<List<Integer>>list=new ArrayList<>(); Stack<TreeNod…

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…

这是悦乐书的第169次更新,第171篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第28题(顺位题号是112).给定二叉树和整数sum,确定树是否具有根到叶路径,使得沿路径的所有值相加等于给定的sum.叶子节点是没有子节点的节点.例如: 给定以下二叉树和sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 返回true,因为存在根到叶的路径5-> 4-> 11-> 2,并且和为22. 本次解题使用的开发工具是eclips…

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] ] 上一道题的延伸,求出所有结果. /**…

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 right at any point in time. Summary: DP, calucate the minimun…

Problem Description: http://oj.leetcode.com/problems/path-sum/ Pretty easy. /** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solu…