【AC自动机】[HDU2222]Keywords Search

这题根本没什么好说的完全模板题目

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <iostream>
using namespace std;
const int MAXN = 10000;
struct State{
    int fail, flag;
    int ch[26];
}p[MAXN*50+10];
int scnt, Bef[MAXN*50+10];
void _init(int n){
    scnt = 0;
    for(int i=0;i<=n;i++){
        memset(p[i].ch, 0, sizeof p[i].ch);
        p[i].fail = p[i].flag = 0;
        Bef[i] = 0;
    }
}
void Add(char *s){
    int now = 0, len = strlen(s);
    for(int i=0;i<len;i++){
        if(!p[now].ch[s[i]-'a']){
            p[now].ch[s[i]-'a'] = ++scnt;
            now = scnt;
        }else now = p[now].ch[s[i]-'a'];
    }
    p[now].flag++;
}
void _initTree(){
    queue<int> que;
    for(int i=0;i<26;i++)
        if(p[0].ch[i])
            que.push(p[0].ch[i]);
    while(!que.empty()){
        int u = que.front();
        que.pop();
        for(int i=0;i<26;i++) if(p[u].ch[i]){
            int v = p[u].ch[i];
            que.push(v);
            int k = p[u].fail;
            while(k && !p[k].ch[i]) k = p[k].fail;
            p[v].fail = p[k].ch[i];
            Bef[v] = p[p[v].fail].flag > 0 ? p[v].fail : Bef[p[v].fail];
        }
    }
}
char ls[1000010];
void match(){
    int len = strlen(ls);
    int u = 0, counter = 0;
    for(int i=0;i<len;i++){
        if(p[u].ch[ls[i]-'a'])
            u = p[u].ch[ls[i]-'a'];
        else{
            int k = p[u].fail;
            while(k && !p[k].ch[ls[i]-'a']) k = p[k].fail;
            u = p[k].ch[ls[i]-'a'];
        }
        int k = u;
        while(k){
            counter += p[k].flag;
            p[k].flag = 0;
            k = Bef[k];
        }
    }
    printf("%d\n", counter);
}
int main(){
    char s[100];
    int T, n;
    scanf("%d", &T);
    while(T--){
        scanf("%d", &n);
        _init(50 * n);
        for(int i=1;i<=n;i++){
            scanf("%s", s);
            Add(s);
        }
        _initTree();
        scanf("%s", ls);
        match();
    }

    return 0;
}