Description 一个正整数，如果从左向右读（称之为正序数）和从右向左读（称之为倒序数）是一样的，这样的数就叫回文数。 任取一个正整数，如果不是回文数，将该数与他的倒序数相加，若其和不是回文数，则重复上述...

Problem Link: https://oj.leetcode.com/problems/recover-binary-search-tree/ We know that the inorder traversal of a binary search tree should be a sorted array. Therefore, we can compare each node w...

Problem Link: https://oj.leetcode.com/problems/validate-binary-search-tree/ We inorder-traverse the tree, and for each node we check if current_node.val > prev_node.val. The code is as follows. ...

import bs4 import requests import urllib2 import time import base64 session=requests.Session() response=session.get('http://oj.blue-whale.me:23331/captcha.php') soup=bs4.BeautifulSoup(response.text...

Problem Link: https://oj.leetcode.com/problems/binary-tree-level-order-traversal/ Traverse the tree level by level using BFS method. # Definition for a binary tree node # class TreeNode: # def...

Problem Link: https://oj.leetcode.com/problems/symmetric-tree/ To solve the problem, we can traverse the tree level by level. For each level, we construct an array of values of the length 2^depth, ...

Problem Link: https://oj.leetcode.com/problems/same-tree/ The following recursive version is accepted but the iterative one is not accepted... # Definition for a binary tree node # class TreeNode:...

ACM竞赛之输入输出以下内容来源于互联网。在ACM程序设计竞赛中，一道题目的所有测试数据是放在一个文本文件中，选手将一道题目的程序提交给评判系统运行，程序从该文件中读取测试数据，再把运行结果输出到另一个...