hdu 2222 Keywords Search (AC自动机-初步-很理解！)

// 看北大课件学习 或者 去我百度空间有资料出处

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <string>
#include <queue>
#include <algorithm>
#define BUG cout << "here\n";
using namespace std;
#define kind 26
#define M 1000010

struct node {
    node* fail;
    node* next[kind];
    int tail;
    node() {
        fail = NULL;
        tail = 0;
        memset(next, 0, sizeof(next));
    }
};
char ch[M];
char word[M];
queue<node*> Q;
int n, m;
void Insert(node* root, char *str) {
    node* p = root;
    int i = 0, index;
    int len = strlen(str);
    for(i = 0; i < len; i++) {
        index = str[i] - 'a';
        if(p->next[index] == NULL) {
            p->next[index] = new node();
        }
        p = p->next[index];
    }
    p->tail++;
}
void BFS_AC(node*& root) { // 指针引用, 就是广搜模式建立失败指针， 核心 ： 当前节点父节点失败指针的儿子
    Q.push(root);
    while(!Q.empty()) {
        node* p = NULL;
        node* t = Q.front();
        Q.pop();
        for(int i = 0; i < kind; i++) {
            if(t->next[i]) {
                p = t->fail;
                while(p) {
                    if(p->next[i]) {
                        t->next[i]->fail = p->next[i];
                        break;
                    }
                    p = p->fail;
                }
                if(!p) {
                    t->next[i]->fail = root;
                }
                Q.push(t->next[i]);
            }
        }
    }
}
void Query(node* root, char *str) {
    int i = 0, index, cnt = 0;
    node *p = root, *tmp;
    int len = strlen(str);

    for(i = 0; i < len; i++) {
        index = str[i] - 'a';
        while(!p->next[index] && p != root) {
            p = p->fail;
        }
        p = p->next[index];
        if(!p) p = root; // 标志了！
        tmp = p;
        while(tmp != root && tmp->tail != -1) {
              cnt += tmp->tail;
              tmp->tail = -1;
              tmp = tmp->fail;
        }
    }
    cout << cnt << endl;
}
int main() {
    int T;
    cin >> T;
    while(T--) {
        scanf("%d", &n);
        node* root = new node();
        for(int i = 0; i < n; i++) {
            scanf("%s", ch);
            Insert(root, ch);
        }
        BFS_AC(root);
        scanf("%s", word);
        Query(root, word);
    }
    return 0;
}