HDU 2222 Keywords Search （AC自动机）

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题目链接：Keywords Search

解析：直接开个end数组，统计一下即可。

PS：AC自动机的代码风格是参考bin神的。

AC代码：

#include <bits/stdc++.h>
using namespace std;

const int max_word = 500005;
const int sigma_size = 26;
const int max_text = 1000005;

struct Trie{
    int next[max_word][sigma_size], fail[max_word], end[max_word];
    int root, L;
    int newnode(){
        for(int i = 0; i < sigma_size; i++) next[L][i] = -1;
        end[L++] = 0;
        return L-1;
    }

    void init(){
        L = 0;
        root = newnode();
    }

    void insert(char buf[]){
        int len = strlen(buf);
        int now = root;
        for(int i = 0; i < len; i++){
            if(next[now][buf[i] - 'a'] == -1) next[now][buf[i] - 'a'] = newnode();
            now = next[now][buf[i] - 'a'];
        }
        end[now] ++;
    }

    void build(){
        queue<int> Q;
        fail[root] = root;
        for(int i = 0; i < sigma_size; i++){
            if(next[root][i] == -1) next[root][i] = root;
            else{
                fail[ next[root][i] ] = root;
                Q.push(next[root][i]);
            }
        }
        while(!Q.empty()){
            int now = Q.front();
            Q.pop();
            for(int i = 0; i < sigma_size; i++){
                if(next[now][i] == -1) next[now][i] = next[ fail[now] ][i];
                else{
                    fail[ next[now][i] ] = next[ fail[now] ][i];
                    Q.push(next[now][i]);
                }
            }
        }
    }

    int query(char buf[]){
        int len = strlen(buf);
        int now = root;
        int res = 0;
        for(int i = 0; i < len; i++){
            now = next[now][ buf[i] - 'a' ];
            int temp = now;
            while(temp != root){
                res += end[temp];
                end[temp] = 0;
                temp = fail[temp];
            }
        }
        return res;
    }

    void debug(){
        for(int i = 0; i < L; i++){
            printf("id = %3d, fail = %3d, end = %3d, chi = [", i, fail[i], end[i]);
            for(int j = 0; j < sigma_size; j++) printf("%2d", next[i][j]);
            printf("]\n");
        }
    }
};

char buf[max_text];
Trie ac;

int main(){
    #ifdef sxk
        freopen("in.txt", "r", stdin);
    #endif // sxk

    int T, n;
    scanf("%d", &T);
    while(T--){
        scanf("%d", &n);
        ac.init();
        for(int i = 0; i < n; i++){
            scanf("%s", buf);
            ac.insert(buf);
        }
        ac.build();
        scanf("%s", buf);
        printf("%d\n", ac.query(buf));
    }
    return 0;
}

HDU 2222 Keywords Search （AC自动机）

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原文地址：http://blog.csdn.net/u013446688/article/details/47170865