LeetCode112. Path Sum java solution

description:
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.

this problem is vary easy, so I will post my code directly.

/** * 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 sum == root.val;        }        else {            return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);        }    }}