```
/**
* 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) {
//start it off with initial sum of 0, pass in root.
return helper(root,0,sum);
}
public boolean helper(TreeNode node,int currSum,int wanted){
if(node==null)
return false;
//node is a leaf
if(node.left==null && node.right==null){
if((node.val+currSum) == wanted) //check if it sumeed up.
return true;
return false;
}
//not a leaf, so recursively try again but with child nodes, pass in current sum + val of this node.
return (helper(node.left,currSum+node.val,wanted) || helper(node.right,currSum+node.val,wanted));
}
}
```