[ACTF2020 新生赛]BackupFile 尝试找到源代码,加上题目是备份文件,猜测备份文件里面有网站的源代码,御剑扫描一下,就扫到index.php 访问index.php.bak 下载源代码: <?php include_once "flag.php"; if(isset($_GET['key'])) { $key = $_GET['key']; if(!is_numeric($key)) { exit("Just num!"); } $key =…

最近蒜头君喜欢上了U型数字,所谓U型数字,就是这个数字的每一位先严格单调递减,后严格单调递增.比如 212212 就是一个U型数字,但是 333333, 9898, 567567, 3131331313,就是不是U型数字. 现在蒜头君问你,[1,100000][1,100000] 有多少U型数字? 提示:请不要输出多余的符号. import java.util.Scanner; public class Main1{ public static String mp[] = new String[…

第一次参加天池新人赛,主要目的还是想考察下自己对机器学习上的成果,以及系统化的实现一下所学的东西.看看自己的掌握度如何,能否顺利的完成一个分析工作.为之后的学习奠定基础. 这次成绩并不好,只是把整个机器学习的流程熟悉了下.我本人总结如下: 步骤一:读懂题目含义,分析赛题的数据 步骤二:特征工程的设计,这部分非常重要,好的特征工程能大大提高模型的准确率 步骤三:训练算法.区分训练集.测试集等. 步骤四:测试模型,看效果如何. 赛题可以去天池的官网查看,里面有赛题说明,赛题数据等等 https://…

两道题都比较简单,所以放到一块记下来吧,不是水博客,师傅们轻点打 BackupFile 题目提示“Try to find out source file!”,访问备份文件/index.php.bak获得index.php源码(其实这里还试了一小会,本来以为是www.zip.bak.zip之类的,最后才想到.bak文件备份) <?php include_once "flag.php"; if(isset($_GET['key'])) { $key = $_GET['key']; i…

0x00 知识点 备份文件 index.php.bak str弱相等被转化为整型 0x01解题 根据提示下载备份文件得到源码 看到==弱相等 且被强制转为整型 http://7d5cccc5-4ecd-44b2-8674-d015237e419a.node3.buuoj.cn/?key=123…

Problem A: pigofzhou的巧克力棒 Description 众所周知,pigofzhou有许多妹子.有一天,pigofzhou得到了一根巧克力棒,他想把这根巧克力棒分给他的妹子们.具体地,这根巧克力棒长为 n,他想将这根巧克力棒折成 n 段长为 1 的巧克力棒,然后分给妹子们. 但是他妹子之一中的 15zhazhahe 有强迫症.若它每次将一根长为 k 的巧克力棒折成两段长为 a 和 b 的巧克力棒,此时若 a=b,则15zhazhahe会得到一点高兴值. pigofzhou想知…

题目描述 Once there was a pig, which was very fond of treasure hunting. One day, when it woke up, it found itself in a strange land of treasure. As for how to come in, or how to go out, no ways to know. Sad. The good news is, it was lucky that it got the…

题目描述 Given an array A with length n  a[1],a[2],...,a[n] where a[i] (1<=i<=n) is positive integer. Count the number of pair (l,r) such that a[l],a[l+1],...,a[r] can be rearranged to form a geometric sequence. Geometric sequence is an array where each…

题目描述 Small koala special love LiaoHan (of course is very handsome boys), one day she saw N (N<1e18) guys standing in a row, because the boys had some strange character,The first time to Liao them will not be successful, but the second time will be su…

题目描述 In country  A, some roads are to be built to connect the cities.However, due to limited funds, only some roads can be built.That is to say,if the limit is 100$, only roads whose cost are no more than 100$ can be built. Now give you n cities, m r…