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