标签:
http://acm.hdu.edu.cn/showproblem.php?pid=2222
一个AC自动机的模板题。用的kuangbin的模板,静态建Trie树。可能遇到MLE的情况要转动态建树。
AC自动机的讲解看这里
http://blog.csdn.net/niushuai666/article/details/7002823
http://blog.csdn.net/mobius_strip/article/details/22549517
/*--------------------------------------------------------------------------------------*/ // Helica‘s header // Second Editions // 2015.11.7 // #include <algorithm> #include <iostream> #include <cstring> #include <ctype.h> #include <cstdlib> #include <cstdio> #include <vector> #include <string> #include <queue> #include <stack> #include <cmath> #include <set> #include <map> //debug function for a N*M array #define debug_map(N,M,G) printf("\n");for(int i=0;i<(N);i++)\ {for(int j=0;j<(M);j++){printf("%d",G[i][j]);}printf("\n");} //debug function for int,float,double,etc. #define debug_var(X) cout<<#X"="<<X<<endl; /*--------------------------------------------------------------------------------------*/ using namespace std; int N,M,T; struct Trie { int next[500010][26],fail[500010],end[500010]; int root,L; int newnode() { for(int i=0;i<26;i++) next[L][i] = -1; end[L++] = 0; return L-1; } void init() { L = 0; root = newnode(); } void insert(char *s) { int len = strlen(s); int now = root; for(int i=0;i<len;i++) { if(next[now][s[i]-‘a‘] == -1) next[now][s[i]-‘a‘] = newnode(); now = next[now][s[i]-‘a‘]; } end[now]++; } void build() { queue <int> Q; fail[root] = root; for(int i=0;i<26;i++) if(next[root][i] == -1) next[root][i] = root; else { fail[next[root][i]] = root; Q.push(next[root][i]); } while(!Q.empty()) { int now = Q.front(); Q.pop(); for(int i=0;i<26;i++) { if(next[now][i] == -1) next[now][i] = next[fail[now]][i]; else { fail[next[now][i]] = next[fail[now]][i]; Q.push(next[now][i]); } } } } int query(char *s) { int len = strlen(s); int now = root; int ans = 0; for(int i=0;i<len;i++) { now = next[now][s[i]-‘a‘]; int temp = now; while(temp != root) { ans += end[temp]; end[temp] = 0; temp = fail[temp]; } } return ans; } void debug() { for(int i=0;i<L;i++) { printf("id = %3d,fail = %3d,end = %3d,chi = [",i,fail[i],end[i]); for(int j=0;j<26;j++) printf("%2d",next[i][j]); printf("]\n"); } } }; char buf[1000100]; Trie ac; int main() { scanf("%d",&T); while(T--) { ac.init(); scanf("%d",&N); for(int i=0;i<N;i++) { scanf("%s",buf); ac.insert(buf); } ac.build(); //ac.debug(); scanf("%s",buf); printf("%d\n",ac.query(buf)); } }
第N次入门AC自动机。。。成功。。。
标签:
原文地址:http://www.cnblogs.com/helica/p/5037814.html