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);
}
};