[Leetcode]Same Tree

/** * 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        if(p == NULL) return q == NULL;        if(q == NULL) return p == NULL;        return p->val == q->val && isSameTree(p->left, q->left) && isSameTree(p->right, q->right);    }};