/** * 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) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        return isSame(p,q);    }    bool isSame(TreeNode *p,TreeNode *q)    {        if(p==NULL&&q==NULL)        return true;        if(p!=NULL&&q!=NULL)        {            if(p->val==q->val)            {                return isSame(p->left,q->left)&&isSame(p->right,q->right);            }            else            {                return false;            }        }        else return false;    }};