面试题18：如何判断两棵二叉树是否相同？

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.

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     bool isSameTree(TreeNode *p, TreeNode *q) {
13         if(p == nullptr && q == nullptr) return true;
14         else if(p == nullptr || q == nullptr){
15             return false;
16         }else if(p->val == q->val){
17             if(isSameTree(p->left,q->left) && isSameTree(p->right,q->right)){
18                 return true;
19             }else{
20                 return false;
21             }
22         }else{
23             return false;
24         }
25     }
26 };

 

posted @ 2017-05-15 22:57  wxquare  阅读(1703)  评论(0)  编辑  收藏  举报