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.

Java:

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

Path Sum