Same Tree

Same Tree 

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

 1 /**
 2  * Definition for binary tree
 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(null == p && null == q)
13             return true;
14         if(null == p || null == q)
15             return false;
16         else{
17             return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
18         }
19     }
20 }