【LeetCode】Path Sum 解题报告

标签（空格分隔）： LeetCode

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题目地址：https://leetcode.com/problems/path-sum/#/description

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 the below binary tree and sum = 22,

          5         / \        4   8       /   / \      11  13  4     /  \      \    7    2      1

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

Ways

这个题要背下来！！

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean hasPathSum(TreeNode root, int sum) {        if(root == null){            return false;        }        if(root.left == null && root.right == null){            return root.val == sum;        }        return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);    }}

Date

2017 年 5 月 12 日