原题地址：https://oj.leetcode.com/problems/path-sum/
题意：
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.
解题思路：使用递归解决。
代码：
# Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution: # @param root, a tree node # @param sum, an integer # @return a boolean def hasPathSum(self, root, sum): if root == None: return False if root.left == None and root.right == None: return root.val == sum return self.hasPathSum(root.left, sum - root.val) or self.hasPathSum(root.right, sum - root.val)
[leetcode]Path Sum @ Python,布布扣,bubuko.com
原文：http://www.cnblogs.com/zuoyuan/p/3752469.html