AC自动机模板（hdu2222）

具体学习参考https://blog.csdn.net/creatorx/article/details/71100840

模板来自kuangbin大神，HDU2222模板题

//======================
// HDU 2222
// 求目标串中出现了几个模式串
//====================
#include
using namespace std;
struct Trie
{
    int next[500010][26],fail[500010],end[500010];//end表示有多少单词以这个结点结尾
    int root,L;
    int newnode()
    {
        for(int i = 0; i < 26; 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()
    {
        queueQ;
        fail[root] = root;
        for(int i = 0; i < 26; 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 < 26; 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 < 26; j++)
                printf("%2d",next[i][j]);
            printf("]\n");
        }
    }
};
char buf[1000010];
Trie ac;
int main()
{
    int T;
    int 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;
}