hdu2222-Keywords Search AC自动机

题意：给一个字符串，和n个单词，问出现过多少个单词。

思路：ac自动机模板题。注意每个单词只能被算一次

代码：

 

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std ;
const int maxw = 26;
const int maxn = 10005;
const int time = 55;
const int maxs = 1000003;
struct DFAAC{
    int tire[maxn*time][maxw];
    int fail[maxn*time];
    int  tag[maxn*time];
    bool vis[maxn*time];
    int root ,P;
    int New(){
        tag[P] = 0;
        for(int i=0;i<maxw;i++)
            tire[P][i] = 0;
        return P++;
    }
    void Init(){
        P=0; root = New();
    }
    void Insert(char ch[]){
        int now = root;
        for(int i=0;ch[i];i++)
        {
            int &nxt = tire[now][ch[i]-'a'];

            if(nxt==0)
               nxt = New();
            now = nxt;
        }
        tag[now]++;
    }
    void built(){
        queue<int>Q;
        for(int i=0;i<maxw;i++){
            int &x = tire[root][i];
            if(x!=0){
                Q.push(x);
                fail[x]=0;
            }
         }
         while(!Q.empty()){
            int u = Q.front();
            Q.pop();
            for(int i=0;i<maxw;i++){
                int &v = tire[u][i];
                if(v){
                    fail[v] = tire[fail[u]][i];
                   // tag[u] += tag[fail[u]];
                    Q.push(v);
                }
                else v = tire[fail[u]][i];
            }
         }
    }
    int quert(char ch[]){
        memset(vis,0,sizeof(vis));
        int ret = 0;
        int now = root;
        for(int i=0;ch[i];i++){
             now = tire[now][ch[i]-'a'];
             int tmp = now;
             while(tmp!=0){
                if(vis[tmp]) break;
                ret += tag[tmp];
                vis[tmp] = 1;
                //tag[tmp] = 0;
                tmp = fail[tmp];
            }
        }
        return ret;
    }
};
char ch[maxs];
int n , t;
DFAAC ac;
int main()
{
    scanf("%d",&t);
    while(t--){
       scanf("%d",&n);
        ac.Init();
       while(n--){
            scanf("%s",ch); ac.Insert(ch);
        }
        ac.built();
        scanf("%s",ch);
        printf("%d\n",ac.quert(ch));
    }

}