/**

* Definition for binary tree

* struct TreeNode {

* int val;

* TreeNode *left;

* TreeNode *right;

* TreeNode(int x) : val(x), left(NULL), right(NULL) {}

* };

*/

class Solution {

public:

bool isSameTree(TreeNode *p, TreeNode *q) {

if(p == nullptr && q == nullptr) return true;

else if(p && q == nullptr) return false;

else if(p == nullptr && q) return false;

if(p->val != q->val) return false;

else return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);

}

};