AC自动机模板

#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
#define full(a, b) memset(a, b, sizeof a)
#define __fastIn ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
using namespace std;
using LL = long long;
inline int lowbit(int x){ return x & (-x); }
inline int read(){
    int ret = 0, w = 0; char ch = 0;
    while(!isdigit(ch)){
        w |= ch == '-', ch = getchar();
    }
    while(isdigit(ch)){
        ret = (ret << 3) + (ret << 1) + (ch ^ 48);
        ch = getchar();
    }
    return w ? -ret : ret;
}
template <typename A>
inline A __lcm(A a, A b){ return a / __gcd(a, b) * b; }
template <typename A, typename B, typename C>
inline A fpow(A x, B p, C lyd){
    A ans = 1;
    for(; p; p >>= 1, x = 1LL * x * x % lyd)if(p & 1)ans = 1LL * x * ans % lyd;
    return ans;
}
const int N = 200;
const int M = 100005;
int n, tot, cnt, trie[M][26], ending[M], iex[N], fail[M], freq[M], head[M];
string s[N], t;
struct Edge { int v, next; } edge[M<<1];

void addEdge(int a, int b){
    edge[cnt].v = b, edge[cnt].next = head[a], head[a] = cnt ++;
}

void init(){
    tot = cnt = 0;
    full(ending, 0), full(iex, 0), full(freq, 0);
    full(trie, 0), full(head, -1);
}

void insert(const string &buf, int j){
    int p = 0;
    for(int i = 0; i < buf.size(); i ++){
        int ch = buf[i] - 'a';
        if(!trie[p][ch]) trie[p][ch] = ++ tot;
        p = trie[p][ch];
    }
    ending[p] ++, iex[j] = p;
}

void getFail(){
    full(fail, 0);
    queue<int> q;
    for(int i = 0; i < 26; i ++){
        if(trie[0][i]) q.push(trie[0][i]);
    }
    while(!q.empty()){
        int s = q.front(); q.pop();
        for(int i = 0; i < 26; i ++){
            if(trie[s][i]){
                fail[trie[s][i]] = trie[fail[s]][i];
                q.push(trie[s][i]);
            }
            else trie[s][i] = trie[fail[s]][i];
        }
    }
}

void buildFailTree(){
    for(int i = 1; i <= tot; i ++){
        addEdge(fail[i], i), addEdge(i, fail[i]);
    }
}

void dfs(int s, int fa){
    for(int i = head[s]; i != -1; i = edge[i].next){
        int u = edge[i].v;
        if(u == fa) continue;
        dfs(u, s);
        freq[s] += freq[u];
    }
}

void query(const string &buf){
    int p = 0, maxl = 0;
    for(int i = 0; i < buf.size(); i ++){
        p = trie[p][buf[i] - 'a'];
        freq[p] ++;
    }
    dfs(0, 0);
    for(int i = 1; i <= n; i ++){
        maxl = max(maxl, freq[iex[i]]);
    }
    cout << maxl << endl;
    for(int i = 1; i <= n; i ++){
        if(maxl == freq[iex[i]]){
            cout << s[i] << endl;
        }
    }
}

int main(){

    __fastIn;

    while(cin >> n && n){
        init();
        for(int i = 1; i <= n; i ++){
            cin >> s[i];
            insert(s[i], i);
        }
        getFail(), buildFailTree();
        cin >> t;
        query(t);
    }
    return 0;
}

洛谷P3796 AC自动机

原文：https://www.cnblogs.com/onionQAQ/p/11373923.html