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) {        if(p==NULL || q== NULL)            return p==q;        if(p->val!=q->val)            return false;        bool flag_left = isSameTree(p->left,q->left);        bool flag_right = isSameTree(p->right,q->right);        return flag_left && flag_right;    }};