[LeetCode] Path Sum

Total Accepted: 11233Total Submissions:37402

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.

 

/** * Definition for binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean hasPathSum(TreeNode root, int sum) {        return traverse(root, 0, sum);    }        public boolean traverse(TreeNode root, int sum, int target) {        if (root == null) return false;                sum += root.val;        if (sum == target && root.left == null && root.right == null) return true;                return traverse(root.left, sum, target) || traverse(root.right, sum, target);    }}