题意 问一个字符串中包含多少种模式串,该字符串的反向串包含也算. 思路 解析一下字符串,简单. 建自动机的时候,通过fail指针建立trie图.这样跑图的时候不再跳fail指针,相当于就是放弃了fail指针. 跑的时候,已经走过的模式串不能二次计数. 代码 附赠一大波样例 #include <iostream> #include <stdio.h> #include <queue> #include <string.h> using namespace st…

  Computer Virus on Planet Pandora Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 1353   Accepted: 256 Description Aliens on planet Pandora also write computer programs like us. Their programs only consist of capital letters (‘A’ to ‘Z’…

Computer Virus on Planet Pandora Time Limit: 6000/2000 MS (Java/Others)    Memory Limit: 256000/128000 K (Java/Others)Total Submission(s): 2975    Accepted Submission(s): 833 Problem Description     Aliens on planet Pandora also write computer progra…

Description Aliens on planet Pandora also write computer programs like us. Their programs only consist of capital letters (‘A’ to ‘Z’) which they learned from the Earth. On planet Pandora, hackers make computer virus, so they also have anti-virus sof…

题目大意 给定一个文本串T,然后给定n个模式串,问有多少个模式串在文本串中出现,正反都可以 题解 建立好自动机后.把文本串T正反各匹配一次,刚开始一直TLE...后面找到原因是重复的子串很多以及有模式串是另外一个模式串的子串这种情况也很多~~~,所以我们用数组标记一下就好了~~~改了交上去之后是WA,最后发现时visit数组初始化错地方了.... 代码: #include <iostream> #include <cstring> #include <algorithm>…

题目连接:hdu 3695 Computer Virus on Planet Pandora 题目大意:给定一些病毒串,要求推断说给定串中包括几个病毒串,包括反转. 解题思路:将给定的字符串展开,然后匹配一次后反转后再匹配一次. #include <cstdio> #include <cstring> #include <queue> #include <vector> #include <iostream> #include <algor…

Computer Virus on Planet Pandora Time Limit: 6000/2000 MS (Java/Others)    Memory Limit: 256000/128000 K (Java/Others)Total Submission(s): 2578    Accepted Submission(s): 713 Problem Description     Aliens on planet Pandora also write computer progra…

F - Computer Virus on Planet Pandora Time Limit:2000MS     Memory Limit:128000KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 3695 Appoint description:  System Crawler  (2014-11-05) Description     Aliens on planet Pandora also write…

Computer Virus on Planet Pandora Time Limit: 6000/2000 MS (Java/Others)    Memory Limit: 256000/128000 K (Java/Others) Total Submission(s): 4090    Accepted Submission(s): 1072 Problem Description     Aliens on planet Pandora also write computer prog…

HDU-3695 Computer Virus on Planet Pandora 题意:电脑中病毒了, 现在n钟病毒指令, 然后有一个电脑指令, 看一下这个电脑指令中了几个病毒, 如果电脑种了某一个病毒, 那么就有子串是病毒指令, 或者 子串的反串是病毒指令, 现在问电脑指令一共感染了多少病毒. 题解:AC自动机,然后正向匹配一遍, 反向匹配一遍. 代码: #include<bits/stdc++.h> using namespace std; #define LL long long #d…

Problem's Link Mean: 有n个模式串和一篇文章,统计有多少模式串在文章中出现(正反统计两次). analyse: 好久没写AC自动机了,回顾一下AC自动机的知识. 本题在构造文章的时候需要仔细一点,其他没什么Trick,和普通AC自动机做法一样: build Trie  --->  build Fail_Ptr ---> matching_and_count Time complexity: O(N*L+M) Source code:  /* * this code is m…

题意:给t.n,t个案例,n个字符串 下面给n+1个字符串,n个互不相同的小串,最后一个是模式串 模式串会出现[qx]的形式,q为数字,x为一个字母 问n个小串在模式串中出现的个数,正着出现.反着出现都算. 蛮裸的ac自动机,本来想着在query里面把找到过的end清零,把模式串展开正着反着找两遍,那即使再找到加零也不影响.但是超时了... 于是把找到过的end标为-1,-1了就不再找下去,就可以了~上代码 #include <cstdio> #include <cstdlib>…

主题链接:option=com_onlinejudge&Itemid=8&page=show_problem&problem=3104">点击打开链接 题意: case数 n个模式串 一个母串. 问:n个模式串出现的种数(一个模式串多次出现仅仅算一次) 对于 "ABC" , 若母串出现了"CBA"这种反串.也算出现了. 所以: 1 ABC CBA ans = 1 #include <cstdio> #include…

题意:有n种病毒序列(字符串),一个模式串,问这个字符串包括几种病毒. 包括相反的病毒也算.字符串中[qx]表示有q个x字符.具体见案列. 0 < q <= 5,000,000尽然不会超,无解 3 2 AB DCB DACB 3 ABC CDE GHI ABCCDEFIHG 4 ABB ACDEE BBB FEEE A[2B]CD[4E]F   Sample Output 0 3 2 Hint In the second case in the sample input, the revers…

http://acm.hust.edu.cn/vjudge/problem/33057 题意:在二维文本串T中查找一个二维模板串P出现了多少次. 题解: 拆分模板串P的每一行,建AC自动机.拆分文本串T的每一行,在自动机中与P匹配,ct[i][j]表示以点(i,j)为左上角.与P等大的矩形有多少个对应的行与P匹配.最后ct[i][j]==P的行数的i,j就是一个匹配点,ans++.注意:1.原本我在trie的叶子用动态数组维护了一个表示这一行是P的第几行的数组,但是超时了,后来看了LRJ的代码,…

题意: 给一个母串和多个模式串,求模式串在母串后翻转后的母串出现次数的的总和. 分析: 模板题 /*#include <cstdio> #include <cstring> #include <cmath> #include <queue> #include <algorithm> using namespace std; const int maxnode = 250*1000+10000; const int sigma_size = 26;…

题目链接:http://icpc.njust.edu.cn/Problem/Hdu/3695/ 不加last指针的AC自动机会T,原因是他费了很多功夫在跳转上,而last指针是直接直到跳转的终止位置,直接跳转到终止位置上,所以只有一次跳转.未优化的fail指针最坏的情况下复杂度是O(|S|*|T|),其中|S|是模式串长度的均值,|T|是文本串的 长度. 代码如下: #include<bits/stdc++.h> using namespace std; #define LL long lon…

题中有一个坑点,就是模式串可以相同,并且全部计数. #include <bits/stdc++.h> using namespace std; const int maxn=1e6+10; const int N=maxn; char str[maxn]; struct Dfa { int trie[N][26],cnt; int e[N]; int fail[N]; char ch; void init(char c) { memset(trie,0,sizeof(trie)); memse…

What's Aho-Corasick automaton? 一种多模式串匹配算法,该算法在1975年产生于贝尔实验室,是著名的多模式匹配算法之一. 简单的说,KMP用来在一篇文章中匹配一个模式串:但如果有多个模式串,需要在一篇文章中把出现过的模式串都匹配出来,就需要Aho-Corasick automaton算法了. My Understanding About Aho-Corasick automaton   我的理解:Aho-Corasick automaton = Trie + KMP…

Computer Virus on Planet Pandora Time Limit: 6000/2000 MS (Java/Others)    Memory Limit: 256000/128000 K (Java/Others) Total Submission(s): 1846    Accepted Submission(s): 510 Problem Description     Aliens on planet Pandora also write computer progr…

这章对现在的我来说有点难,要是不写点东西,三天后怕是就一无所有了. 但写这个没有营养的blog的目的真的不是做题或提升,只是学习学习代码和理解一些概念. 现在对AC自动机的理解还十分浅薄,这里先贴上目前我看过的文章: 深入理解Aho-Corasick自动机算法 AC 自动机学习笔记 AC自动机相比Trie多了失配边,结点到结点间的状态转移,结点到根的状态转移. 这里fail的定义是:使当前字符失配时跳转到另一段从root开始每一个字符都与当前已匹配字符段某一个后缀完全相同且长度最大的位置继续匹配…

Aho-Corasick automaton,该算法在1975年产生于贝尔实验室,是著名的多模式匹配算法之一. KMP算法很好的解决了单模式匹配问题,如果有了字典树的基础,我们可以完美的结合二者解决多模式匹配问题. 在KMP算法中,我们预先根据待匹配串自身的信息得到失配指针,使得在每次匹配不成功后,可以不再去处理模式串的已匹配过的部分,进而使得复杂度降为O(N). 对于多模式串匹配问题,当一个模式串与待匹配串不匹配时,失配指针可以指向任意一个串,这就需要我们利用字典树来组织所有模式串并得到失配指…

题目描述 Farmer John has purchased a subscription to Good Hooveskeeping magazine for his cows, so they have plenty of material to read while waiting around in the barn during milking sessions. Unfortunately, the latest issue contains a rather inappropria…

Detect the Virus Time Limit: 2 Seconds      Memory Limit: 65536 KB One day, Nobita found that his computer is extremely slow. After several hours' work, he finally found that it was a virus that made his poor computer slow and the virus was activated…

题目链接:https://vjudge.net/problem/ZOJ-3430 Detect the Virus Time Limit: 2 Seconds      Memory Limit: 65536 KB One day, Nobita found that his computer is extremely slow. After several hours' work, he finally found that it was a virus that made his poor…

One day, Nobita found that his computer is extremely slow. After several hours' work, he finally found that it was a virus that made his poor computer slow and the virus was activated by a misoperation of opening an attachment of an email. Nobita did…

地址:http://poj.org/problem?id=2778 题目: DNA Sequence Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 15453   Accepted: 5964 Description It's well known that DNA Sequence is a sequence only contains A, C, T and G, and it's very useful to an…

Censored! Time Limit: 5000MS   Memory Limit: 10000K Total Submissions: 6956   Accepted: 1887 Description The alphabet of Freeland consists of exactly N letters. Each sentence of Freeland language (also known as Freish) consists of exactly M letters w…

DNA Sequence Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 9899   Accepted: 3717 Description It's well known that DNA Sequence is a sequence only contains A, C, T and G, and it's very useful to analyze a segment of DNA Sequence,For exa…

题目链接:  http://poj.org/problem?id=3691 题目大意:给定N个致病DNA片段以及一个最终DNA片段.问最终DNA片段最少修改多少个字符,使得不包含任一致病DNA. 解题思路: 首先说一下AC自动机在本题中的作用. ①字典树部分:负责判断当前0~i个字符组成的串是否包含致病DNA,这部分靠字典树上的cnt标记完成. ②匹配部分:主要依赖于匹配和失配转移关系的计算,这部分非常重要,用来构建不同字符间状态压缩的转移关系(代替反人类的位运算). 这也是必须使用AC自动机而…