AC自动机模板题 HDU - 2222

Keywords Search  HDU - 2222

贴个vj的链接https://vjudge.net/problem/HDU-2222

题意：T组数据，n个单词，再给你一个串，看有几个单词在这个串里面出现过

Sample Input

1
5
she
he
say
shr
her
yasherhs

Sample Output

3

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
using namespace std;

const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;

const int N = 5e5 + 1000;
int fa[N], trie[N][30], tot, vis[N];

void build(string s){
    int len = s.size();
    int pos = 0;
    for(int i = 0; i < len; i++){
        int son = s[i] - 'a';
        if(!trie[pos][son]) trie[pos][son] = ++tot;
        pos = trie[pos][son];
    }
    vis[pos]++;
}
void getfail(){
    queue<int> q;
    for(int i = 0, p; i < 26; i++){
        p = trie[0][i];
        if(p){
            fa[p] = 0;
            q.push(p);
        }
    }
    while(q.size()){
        int now = q.front();
        q.pop();
        for(int i = 0; i < 26; i++){
            int u = trie[now][i];
            if(u){
                q.push(u);
                fa[u] = trie[fa[now]][i];
            }
            else trie[now][i] = trie[fa[now]][i];
        }
    }
}

int getans(string s){
    int now = 0, ans = 0;
    for(int i = 0; i < s.size(); i++){
        now = trie[now][s[i]-'a'];
        for(int j = now; j && vis[j]!=-1; j = fa[j]){
            ans+=vis[j];
            vis[j] = -1;
        }
    }
    return ans;
}

int main(){
    int t; cin >> t;
    fa[0] = 0;
    while(t--){
        memset(trie, 0, sizeof(trie));
        memset(vis, 0, sizeof(vis));
        tot = 0;
        int n; cin >> n;
        string s;
        for(int i = 1; i <= n; i++){
            cin >> s;
            build(s);
        }
        getfail();
        cin >> s;
        cout << getans(s) << endl;
    }
}