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 a binary tree node. * 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) {        TreeNode *ph = p;        TreeNode *qh = q;        if(ph == NULL && qh == NULL)            return true;        if(ph != NULL && qh != NULL && ph->val == q->val)        {            if(isSameTree(ph->left, qh->left) && isSameTree(ph->right, qh->right))                return true;            else                return false;        }        else            return false;    }};