[算法]AC自动机 [题解]本题注意题意是多少关键字能匹配而不是能匹配多少次,以及可能有重复单词. 询问时AC自动机与KMP最大的区别是因为建立了trie,所以对于目标串T与自动机串是否匹配只需要直接访问对应结点,而不用真的比较. 因此可以预处理出拥有对应节点的失配串,不用一次一次跑前跑去找一样的. 然后还有就是一个结点可能对应多个串,所以需要last使统计答案完整. AC自动机的细节标注在代码里了. AC自动机过程: [trie] for 长度 if(!ch[u][c])初始化,ch[u][c…

题目 传送门:QWQ 分析 $ AC $自动机模板,黈力的码风真的棒极了,这是我抄他的. 还有 题号不错 代码 #include <cstdio> #include <cstring> #define N 500007 using namespace std; ],fail[N],cur,j,end[N],q[N],vis[N],ans[N],end2[N],end3[N]; ]; int find(int cur,int i){ if(!cur)return rt; if(son…

AC自动机基础题. #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <queue> using namespace std; #define MAXL 1000005 #define TRIEN 26 ]; typedef struct Trie { int n; Trie *fail; Trie *next[TRIEN];…

HDU 2222 Keywords Search(查询关键字) Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others) [Description] [题目描述] In the modern time, Search engine came into the life of everybody like Google, Baidu, etc. Wiskey also wants to br…

传送门:pid=4888">[HDU]4888 Redraw Beautiful Drawings 题目分析: 比赛的时候看出是个网络流,可是没有敲出来.各种反面样例推倒自己(究其原因是不愿意写暴力推断的).. 首先是简单的行列建边.源点向行建边.容量为该行元素和,汇点和列建边.容量为该列元素和.全部的行向全部的列建边,容量为K. 跑一次最大流.满流则有解,否则无解. 接下来是推断解是否唯一. 这个题解压根没看懂.还是暴力大法好. 最简单的思想就是枚举在一个矩形的四个端点.设A.D为主对角…

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…

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 users type some keywords t…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 44687    Accepted Submission(s): 14103 Problem Description In the modern time, Search engine came into the life of everybody li…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 57353    Accepted Submission(s): 18820 Problem Description In the modern time, Search engine came into the life of everybody li…

Keywords Search Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 50451    Accepted Submission(s): 16236 Problem Description In the modern time, Search engine came into the life of everybody lik…