luogu P3808 模板AC自动机（简单版）

Posted 2020-10-02 ZlycerQan

二次联通门 : luogu P3808 【模板】AC自动机（简单版）

 

 

 

 

/*
    luogu P3808 【模板】AC自动机（简单版）

    手速越来越快了
    10分钟一个AC自动机
    一遍过编译 + 一边AC
    
    感觉不错
    我也就做做板子题了。。
     
*/
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>

#define Max 1000009

void read (int &now)
{
    register char word = getchar ();
    for (now = 0; !isdigit (word); word = getchar ());
    for (; isdigit (word); now = now * 10 + word - ‘0‘, word = getchar ());
}

struct Trie_Data
{
    Trie_Data *child[26];
    
    Trie_Data *Fail;
    int Count;
    
    Trie_Data ()
    {
        for (int i = 0; i < 26; i ++)
            this->child[i] = NULL;
        
        Fail = NULL;
        Count = 0;
    }
};

Trie_Data *Root; 
std :: queue <Trie_Data *>Queue;

class AC_Type
{

    public :
        
        void Insert (char *key)
        {
            Trie_Data *now = Root;
            
            Trie_Data *pos;
            int Id;
            int Len = strlen (key);
            for (int i = 0; i < Len; i ++)
            {
                Id = key[i] - ‘a‘;
                if (now->child[Id] == NULL)
                    now->child[Id] = new Trie_Data;                    
                now = now->child[Id];
            }
            now->Count ++;
        }
        
        void AC_Build ()
        {
            Queue.push (Root); 
            Trie_Data *now;
            Trie_Data *pos;
            while (!Queue.empty ())
            {
                pos = NULL;
                now = *&Queue.front ();
                Queue.pop ();
                for (int i = 0; i < 26; i ++)
                {
                    if (now->child[i] == NULL)
                        continue;
                    if (now == Root)
                        now->child[i]->Fail = Root;
                    else
                    {
                        pos = now->Fail;
                        for (; pos; pos = pos->Fail)
                            if (pos->child[i] != NULL)
                            {
                                now->child[i]->Fail = pos->child[i];
                                break;
                            }
                        if (pos == NULL)
                            now->child[i]->Fail = Root;
                    }
                    Queue.push (now->child[i]); 
                }  
            }
        }
        
        int Query (char *key)
        {
            int Answer = 0;
            int Len = strlen (key);
            
            int Id;
            Trie_Data *now = Root;
            for (int i = 0; i < Len; i ++)
            {
                Id = key[i] - ‘a‘;
                while (now->child[Id] == NULL && now != Root)
                    now = now->Fail;
                now = now->child[Id];
                if (now == NULL)
                    now = Root;
                Trie_Data *pos = now;
                for (; pos != Root && pos->Count >= 0; pos = pos->Fail)
                {
                    Answer += pos->Count;
                    pos->Count = -1;
                }
            }
            return Answer;
        }
};

AC_Type Make;

char line[Max];

int main (int argc, char *argv[])
{
    int T, N;
    Root = new Trie_Data;
    for (read (N); N --; )
    {
        scanf ("%s", line);
        Make.Insert (line); 
    }
    Make.AC_Build (); 
    scanf ("%s", line);
    printf ("%d\n", Make.Query (line)); 
    
    return 0;
}