1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 public class Solution {
11     public boolean isSameTree(TreeNode p, TreeNode q) {
12         if(p==null&& q==null){
13             return true;
14         }
15         if(p==null&&q!=null || q!=null&&q==null){
16             return false;
17         }
18         if(p!=null&&q!=null){
19             return (p.val==q.val)&&isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);    
20         }
21         return false;
22     }
23 }