首先,有这样一道题: 给你一个单词W和一个文章T,问W在T中出现了几次(原题见POJ3461). OK,so easy~ HASH or KMP 轻松解决. 那么还有一道例题: 给定n个长度不超过50的由小写英文字母组成的单词准备查询,以及一篇长为m的文章,问:文中出现了多少个待查询的单词(原题见POJ3630). OK,依然so easy~ 字典树(Trie)轻松解决. 那么,如果你说,什么是KMP和Trie,那么恭喜你啊…… 建议大家要在看这篇博客之前做到: 如果你能看到这里,说明你已经熟练…

地址:http://acm.split.hdu.edu.cn/showproblem.php?pid=2222 题目: Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 56558    Accepted Submission(s): 18493 Problem Description In the mo…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 50435    Accepted Submission(s): 16233 Problem Description In the modern time, Search engine came into the life of everybody li…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2222 Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 65272    Accepted Submission(s): 21782 Problem Description In the modern ti…

AC自动机模板题,给你n个模式串和一个文本串,问你有几个模式串在文本串出现过. 注意防止重复统计 这里推荐一波郭大爷的介绍,简单易懂. http://www.bilibili.com/video/av6295004/ 这个视频里的hdu2222代码好像有点问题,我现在这份代码已经更改. #include<cstdio> #include<cstring> #include<queue> using namespace std; queue<int>q; in…

/** 链接:http://acm.hdu.edu.cn/showproblem.php?pid=2222 题意:题意:给定N(N <= 10000)个长度不大于50的模式串,再给定一个长度为L(L <= 106)目标串,求目标串出现了多少个模式串. 思路:ac自动机入门题..直接插入查询. 唯一需要特殊考虑的是存在多个相同的字符串:相同的字符串会在字典书上覆盖原先的. 解决方法1:用map<string,int>标记同一种字符串.之后利用标记来统计. 解决方法2:用num[i]标…

https://vjudge.net/problem/HDU-2222 题意:给几个模式串和一个文本串,问文本串中包含几个模式串. 思路:贴个板子不解释. #include<cstdio> #include<cstring> #include<queue> using namespace std; const int N=26; const int MAXN=500005; struct Trie{ int next[MAXN][N],fail[MAXN],end[MA…

指针我一般都会出错,所以还是自己写数组版本. In the modern time, Search engine came into the life of everybody like Google, Baidu, etc. Wiskey also wants to bring this feature to his image retrieval system. Every image have a long description, when users type some keyword…

HDU2222 Keywords Search Problem Description In the modern time, Search engine came into the life of everybody like Google, Baidu, etc. Wiskey also wants to bring this feature to his image retrieval system. Every image have a long description, when us…

[HDU2222]Keywords Search Problem Description In the modern time, Search engine came into the life of everybody like Google, Baidu, etc.Wiskey also wants to bring this feature to his image retrieval system.Every image have a long description, when use…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 46676    Accepted Submission(s): 14858 Problem Description In the modern time, Search engine came into the life of everybody lik…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 79383    Accepted Submission(s): 27647 Problem Description In the modern time, Search engine came into the life of everybody lik…

题目大意: 给出多个模式串和一个主串,求多少个模式串在主串中出现过. 传送门 这是一道AC自动机的模板题. 在学习AC自动机之前,首先要学习WA自动机.TLE自动机和MLE自动机(雾 AC自动机是一种多模式串匹配算法. AC自动机概述: *fail指针:指向失配时的匹配节点: 1)构建字典树 2)初始化fail指针: 一条$fail$指针链可以理解为一个串连所有后缀相同的字符串的链表,并且所有链表的末端都指向trie的根.我们定义沿着节点$v$的$fail$指针走到根部的路径为v的trie链表.…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 68211    Accepted Submission(s): 23017 Problem Description In the modern time, Search engine came into the life of everybody lik…

题目链接 题意:每个文本串的出现次数 分析:入门题,注意重复的关键字算不同的关键字,还有之前加过的清零.   新模板,加上last跑快一倍 #include <bits/stdc++.h> struct AC { static const int NODE = 10000 * 50 + 5; static const int SIZE = 26; int ch[NODE][SIZE], fail[NODE], last[NODE]; int end[NODE]; int sz; void cl…

点击打开链接题目链接 Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 42838    Accepted Submission(s): 13488 Problem Description In the modern time, Search engine came into the life of eve…

玄武密码 给若干模式串和一个文本串.求每个模式串在文本串上能匹配的最大前缀长度. N<=10^7,M<=10^5,每一段文字的长度<=100. jklover的题解 将模式串建成一个 AC 自动机,匹配文本串的时候往前暴力跳,跳到第一个合法的位置即可. 时间复杂度:线性. co int N=1e7+1,S=4; int n,m; int len[N]; namespace AC { int idx; int id(char x) { switch(x) { case 'E': retur…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 35683    Accepted Submission(s): 11520 Problem Description In the modern time, Search engine came into the life of everybody like…

Keywords Search Description In the modern time, Search engine came into the life of everybody like Google, Baidu, etc.       Wiskey also wants to bring this feature to his image retrieval system.       Every image have a long description, when users…

题目链接:https://cn.vjudge.net/problem/HDU-2222 题意 给一些关键词,和一个待查询的字符串 问这个字符串里包含多少种关键词 思路 AC自动机模版题咯 注意一般情况不需要修改build方法,就像kmp里的getfail一样 一般的题目就是改改insert,query 一开始写的模版总是有问题,懒得改了 直接找的kuangbin的模版[原创]AC自动机小结 注意数组和指针的效率差不了多少,此题同一个算法的指针形式(296ms)比数组(187ms)慢110ms 说…

题目大意:统计一共出现了多少次模板串. 题目分析:AC自动机的模板题.不过这题有坑,相同的模板串不能只算一次. 代码如下: # include<iostream> # include<cstdio> # include<queue> # include<map> # include<string> # include<cstring> # include<algorithm> using namespace std; co…

AC自动机是一种多模式匹配的算法.大概过程如下: 首先所有模式串构造一棵Trie树,Trie树上的每个非根结点都代表一个从根出发到该点路径的字符串. 然后每个结点都计算出其fail指针的值,这个fail指针就指向这个结点所表示字符串的最长存在的后缀所对应的结点,如果不存在就指向根:计算每个结点的fail用BFS,比如当前结点u出队要拓展并计算其孩子结点的fail,v是其第k个孩子,fail[v]的值就是某个fail[fail[fail...[u]]]存在第k孩子结点其第k个孩子结点,如果不存在f…

AC自动机模板,注意!ch,Fail,lab数组的大小不是n而是节点个数,需要认真计算! #include <iostream> #include <algorithm> #include <cstdio> #include <cstring> #include <cmath> #include <ctime> #include <cstdlib> #include <queue> using namespac…

In the modern time, Search engine came into the life of everybody like Google, Baidu, etc. Wiskey also wants to bring this feature to his image retrieval system. Every image have a long description, when users type some keywords to find the image, th…

多模匹配 题目大意:给定很多个字串A,B,C,D,E....,然后再给你目标串str字串,看目标串中出现多少个给定的字串. 经典AC自动机模板题,不多说. #include <iostream> #include <algorithm> #include <functional> #include <string.h> #define MAX 26 using namespace std; struct node { node *fail, *next[MA…

学习AC自动机请戳这里:大神blog........ 自动机的模板: #include <iostream> #include <algorithm> #include <cmath> #include <cstdio> #include <cstdlib> #include <cstring> #include <string> #include <vector> #include <set> #…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2222 题意:有N(N <= 10000)个长度不超过50的模式串和一个长度不超过1e6的文本串.其中模式串可以重复.问有多少文本串在模式串中出现过.(对于相同的模式串次数仍然累加) 思路:ac自动机裸题: KMP是先将文本串进行匹配得到失配边f[];但是并不适用于文本串较长,模式串较多的情况.因为每次查询的时间复杂度为O(n+m).n,m分别为文本串和模式串的长度: ac自动机就是建立在Trie上,…

题意:就是求目标串中出现了几个模式串. 思路:用int型的end数组记录出现,AC自动机即可. #include<iostream> #include<cstdio> #include<cstring> #include<cmath> #include<string> #include<algorithm> #include<queue> #define maxn 500005 int T,n; ]; struct Tri…

题目链接 先整理一发ac自动机模板.. #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <complex> #include <cmath> #include <map> #include <set> #include <string…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2222 思路分析:该问题为多模式匹配问题,使用AC自动机解决:需要注意的问题是如何统计该待查询的字符串包含的关键字: 假设待查找的字符串为str[0..n],则str[i…j]可能为某一个关键字:假设当前正在匹配字符str[k],则以str[i..k]为关键字的所有可能 可能的关键字的最后一个字符为str[k],使用fail指针进行跳转并判断以str[k]结尾的该结点是否为关键字最后一个结点,重复进行…