【luogu P3808 AC自动机（简单版）】 模板

题目链接：https://www.luogu.org/problemnew/show/P3808

#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 1000010;
int n, trie[maxn][27], next[maxn], tot, vis[maxn];
char s[maxn];
queue<int> q;
void _insert(char s[])
{
    int now = 0;
    int len = strlen(s);
    for(int i = 0; i < len; i++)
    {
        int x = s[i]-'a';
        if(!trie[now][x])
        trie[now][x] = ++tot;
        now = trie[now][x];
    }
    vis[now]++;
}
void get_next()
{
    for(int i = 0; i < 26; i++)
    {
        if(trie[0][i])
        {
            next[trie[0][i]] = 0;
            q.push(trie[0][i]);
        }
    }
    while(!q.empty())
    {
        int cnt = q.front(); q.pop();
        for(int i = 0; i < 26; i++)
        {
            if(trie[cnt][i])
            {
                next[trie[cnt][i]] = trie[next[cnt]][i];
                q.push(trie[cnt][i]);
            }
            else
            trie[cnt][i] = trie[next[cnt]][i];
        }
    }
}
int find(char s[])
{
    int now = 0, ans = 0;
    int len = strlen(s);
    for(int i = 0; i < len; i++)
    {
        int x = s[i]-'a';
        now = trie[now][x];
        for(int k = now; k&&~vis[k]; k = next[k])
        {
            ans += vis[k];
            vis[k] = -1;
        }
    }
    return ans;
}
int main()
{
    std::ios::sync_with_stdio(false);
    cin>>n;
    for(int i = 1; i <= n; i++)
    {
        cin>>s;
        _insert(s);
    }
    get_next();
    cin>>s;
    cout<<find(s);
    return 0;
}