HDU 2222Keywords Search （ac自动机）

题意:

多模式串匹配母串,求模式串的出现次数

代码:

////  Created by TaoSama on 2015-10-31//  Copyright (c) 2015 TaoSama. All rights reserved.////#pragma comment(linker, "/STACK:1024000000,1024000000")#include <algorithm>#include <cctype>#include <cmath>#include <cstdio>#include <cstdlib>#include <cstring>#include <iomanip>#include <iostream>#include <map>#include <queue>#include <string>#include <set>#include <vector>using namespace std;#define pr(x) cout << #x << " = " << x << "  "#define prln(x) cout << #x << " = " << x << endlconst int N = 1e6 + 10, INF = 0x3f3f3f3f, MOD = 1e9 + 7;const int M = 5e5 + 10;const int S = 26;int n;char s[N];struct AcAutomata {    int root, sz;    int nxt[M][S], fail[M], cnt[M];    int newNode() {        cnt[sz] = 0;        memset(nxt[sz], -1, sizeof nxt[sz]);        return sz++;    }    void init() {        sz = 0;        root = newNode();    }    void insert(char *s) {        int n = strlen(s);        int u = root;        for(int i = 0; i < n; ++i) {            int &v = nxt[u][s[i] - 'a'];            if(v == -1) v = newNode();            u = v;        }        ++cnt[u];    }    void build() {        queue<int> q;        fail[root] = root;        for(int i = 0; i < S; ++i) {            int &v = nxt[root][i];            if(~v) {                fail[v] = root;                q.push(v);            } else v = root;        }        while(q.size()) {            int u = q.front(); q.pop();            for(int i = 0; i < S; ++i) {                int &v = nxt[u][i];                if(~v) {                    fail[v] = nxt[fail[u]][i];                    q.push(v);                } else v = nxt[fail[u]][i];            }        }    }    int query(char *s) {        int n = strlen(s);        int u = root, ret = 0;        for(int i = 0; i < n; ++i) {            u = nxt[u][s[i] - 'a'];            for(int v = u; v != root; v = fail[v]) {                ret += cnt[v];                cnt[v] = 0;            }        }        return ret;    }} ac;int main() {#ifdef LOCAL    freopen("C:\\Users\\TaoSama\\Desktop\\in.txt", "r", stdin);//  freopen("C:\\Users\\TaoSama\\Desktop\\out.txt","w",stdout);#endif    ios_base::sync_with_stdio(0);    int t; scanf("%d", &t);    while(t--) {        scanf("%d", &n);        ac.init();        for(int i = 1; i <= n; ++i) {            scanf("%s", s);            ac.insert(s);        }        ac.build();        scanf("%s", s);        printf("%d\n", ac.query(s));    }    return 0;}