LeetCode——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

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

中文：给定一二叉树和一个总和，判断此树是否有根到叶的路径上的值之和等于给定的总和的路径。

递归。

public boolean hasPathSum(TreeNode root, int sum) {if (root == null)return false;int temp = sum - root.val;if (temp == 0 && root.left == null && root.right == null)return true;return hasPathSum(root.left, temp) || hasPathSum(root.right, temp);}