hdu 1277 全文检索(AC自动机)

题目链接：hdu 1227 全文检索

题目大意：略。

解题思路：就是普通的匹配问题，注意相同串，以及输出要按照出现顺序呢。

#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

const int maxn = 10000 * 60;
const int maxm = 10005;
const int sigma_size = 10;

struct Aho_Corasick {
    int sz, g[maxn][sigma_size];
    int tag[maxn], fail[maxn], last[maxn];

    int vis[maxm], jump[maxm];
    int c, ans[maxm];

    void init();
    int idx(char ch);
    void insert(char* str, int k);
    void getFail();
    void match(char* str);
    void put(int u);
    void solve(char* s);
}AC;

int N, M;
char s[60005], w[105];

int main () {
    while (scanf("%d%d", &M, &N) == 2) {
        AC.init();
        int mv = 0;
        for (int i = 0; i < M; i++) {
            scanf("%s", s+mv);
            mv += strlen(s+mv);
        }

        for (int i = 1; i <= N; i++) {
            scanf("%*s%*s%*s%s", w);
            AC.insert(w, i);
        }
        AC.solve(s);
    }
    return 0;
}

void Aho_Corasick::solve(char* s) {
    c = 0;
    getFail();
    match(s);

    if (c) {
        printf("Found key:");
        for (int i = 0; i < c; i++)
            printf(" [Key No. %d]", ans[i]);
        printf("\n");
    } else
        printf("No key can be found !\n");
}

void Aho_Corasick::init() {
    sz = 1;
    tag[0] = 0;
    memset(g[0], 0, sizeof(g[0]));
}

int Aho_Corasick::idx(char ch) {
    return ch - '0';
}

void Aho_Corasick::put(int u) {
    int p = tag[u];
    while (p && vis[p] == 0) {
        vis[p] = 1;
        ans[c++] = p;
        p = jump[p];
    }
    if (last[u])
        put(last[u]);
}

void Aho_Corasick::insert(char* str, int k) {
    int u = 0, n = strlen(str);

    for (int i = 0; i < n; i++) {
        int v = idx(str[i]);
        if (g[u][v] == 0) {
            tag[sz] = 0;
            memset(g[sz], 0, sizeof(g[sz]));
            g[u][v] = sz++;
        }
        u = g[u][v];
    }
    jump[k] = tag[u];
    tag[u] = k;
}

void Aho_Corasick::match(char* str) {
    int n = strlen(str), u = 0;
    for (int i = 0; i < n; i++) {
        int v = idx(str[i]);
        while (u && g[u][v] == 0)
            u = fail[u];

        u = g[u][v];

        if (tag[u])
            put(u);
        else if (last[u])
            put(last[u]);
    }
}

void Aho_Corasick::getFail() {
    queue<int> que;

    for (int i  = 0; i < sigma_size; i++) {
        int u = g[0][i];
        if (u) {
            fail[u] = last[u] = 0;
            que.push(u);
        }
    }

    while (!que.empty()) {
        int r = que.front();
        que.pop();

        for (int i = 0; i < sigma_size; i++) {
            int u = g[r][i];

            if (u == 0) {
                g[r][i] = g[fail[r]][i];
                continue;
            }

            que.push(u);
            int v = fail[r];
            while (v && g[v][i] == 0)
                v = fail[v];

            fail[u] = g[v][i];
            last[u] = tag[fail[u]] ? fail[u] : last[fail[u]];
        }
    }
}