[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 && !q)            return true;        else if (!p)            return false;        else if (!q)            return false;        else         {            if (p->val == q->val)                return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);                        else                 return false;        }    }};