Same Tree

一、问题描述

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.

二、思路

递归的难点在于退出条件，即两棵树同时为空则相同，否则任何一颗为空都不相同，

三、代码

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