Leetcode 112. 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.

运用简单的归递解法

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); } }

Path Sum III : http://blog.csdn.net/sundawei2016/article/details/70167903