Path Sum

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