AC自动机 hdu2222

#include <iostream>
using namespace std;

struct Node{
    Node *next[26];
    Node* fail;
    int count;
    Node(){
        for (int i = 0; i < 26; i++){
            next[i] = NULL;
        }
        fail = NULL;
        count = 0;
    }
};
char words[51], s[1000001];
Node* d[500001];
void insert(char words[], Node *root){
    int i, len = strlen(words), v;
    Node *p = root;
    for (i = 0; i < len; i++){
        v = words[i] - 'a';
        if (p->next[v] == NULL){
            p->next[v] = new Node();
        }
        p = p->next[v];
    }
    p->count++;
}
void build(Node *root){
    int head, tail, i;
    Node *p, *temp;
    head = 0;
    tail = 0;
    root->fail = NULL;
    d[head] = root;
    while (head <= tail){
        temp = d[head++];
        for (i = 0; i < 26; i++){
            if (temp->next[i] == NULL) continue;
            if (temp == root){
                temp->next[i]->fail = root;
            }
            else{
                p = temp->fail;
                while (p != NULL){
                    if (p->next[i] != NULL){
                        temp->next[i]->fail = p->next[i];
                        break;
                    }
                    p = p->fail;
                }
                if (p == NULL){
                    temp->next[i]->fail = root;
                }
            }
            d[++tail] = temp->next[i];
        }
    }
}

int query(char s[], Node* root){
    int ans = 0, len = strlen(s), i, v;
    Node *p = root, *temp;
    for (i = 0; i < len; i++){
        v = s[i] - 'a';
        while (p->next[v] == NULL && p != root){
            p = p->fail;
        }
        p = (p->next[v] != NULL) ? p->next[v] : root;
        temp = p;
        while (temp != root&&temp->count != -1){
            ans += temp->count;
            temp->count = -1;
            temp = temp->fail;
        }
    }
    return ans;
}

int main(){
    int m, n, i;
    Node *root;
    cin >> m;
    while (m--){
        root = new Node();
        cin >> n;
        for (i = 0; i < n; i++){
            cin >> words;
            insert(words, root);
        }
        build(root);
        cin >> s;
        cout << query(s, root) << endl;
    }
}