LeetCode: 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.

 /**  
  * Definition for binary tree  
  * struct TreeNode {  
  *   int val;  
  *   TreeNode *left;  
  *   TreeNode *right;  
  *   TreeNode(int x) : val(x), left(NULL), right(NULL) {}  
  * };  
  */  

   bool isSameTree(TreeNode *p, TreeNode *q) {  
     if(!p && !q)return true;  
     if(!p || !q)return false;  
     return ((p->val == q->val) && isSameTree(p->left,q->left) && isSameTree(p->right,q->right) );  
   }