LA 4670 Dominating Patterns

题目链接：https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&category=29&page=show_problem&problem=2671

统计文本中模板单词的出现频率。

AC自动机模板题：

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <queue>
#include <algorithm>
using namespace std;

#define SIGMA_SIZE 26
#define MAXNODE 20000
#define TEXT_SIZE 1000005
#define P_SIZE 80
#define P_NUM 160

map<string,int> ms;
struct AhoCorsickAutomata
{
    int cnt[P_NUM];
    int sz;
    int ch[MAXNODE][SIGMA_SIZE];
    int f[MAXNODE];
    int val[MAXNODE];
    int last[MAXNODE];
    void init()
    {
        sz = 1;
        memset(ch[0],0,sizeof(ch[0]));
        memset(cnt,0,sizeof(cnt));
        ms.clear();
    }
    int idx(char c)
    {
        return c - 'a';
    }
    void insert(char *s,int v)
    {
        int u = 0,n = strlen(s);
        for(int i=0; i<n; i++)
        {
            int c = idx(s[i]);
            if(!ch[u][c])
            {
                memset(ch[sz],0,sizeof(ch[sz]));
                val[sz] = 0;
                ch[u][c] = sz++;
            }
            u = ch[u][c];
        }
        val[u] = v;
        ms[string(s)] = v;
    }

    void print(int j)
    {
        if(j)
        {
            cnt[val[j]]++;
            print(last[j]);
        }
    }
    void find(char *T)
    {
        int n = strlen(T);
        int j = 0;
        for(int i=0; i<n; i++)
        {
            int c = idx(T[i]);
            while(j && !ch[j][c]) j = f[j];
            j = ch[j][c];
            if(val[j]) print(j);
            else if(last[j]) print(last[j]);
        }
    }
    void getFail()
    {
        queue<int> q;
        f[0] = 0;
        for(int c = 0; c<SIGMA_SIZE; c++)
        {
            int u = ch[0][c];
            if(u)
            {
                f[u] = 0;
                q.push(u);
                last[u] = 0;
            }
        }
        while(!q.empty())
        {
            int r = q.front();
            q.pop();
            for(int c = 0; c<SIGMA_SIZE; c++)
            {
                int u = ch[r][c];
                if(!u) continue;
                q.push(u);
                int v = f[r];
                while(v && !ch[v][c]) v = f[v];
                f[u] = ch[v][c];
                last[u] = val[f[u]] ? f[u] : last[f[u]];
            }
        }
    }
};
AhoCorsickAutomata ac;
char text[TEXT_SIZE],p[P_NUM][P_SIZE];
int main()
{
/*#ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
#endif*/
    int n;
    while(scanf(" %d",&n)!=EOF && n!=0)
    {
        ac.init();
        for(int i=1; i<=n; i++)
        {
            scanf(" %s",p[i]);
            ac.insert(p[i],i);
        }
        scanf(" %s",text);
        ac.getFail();
        ac.find(text);
        int best = -1;
        for(int i=1; i<=n; i++)
        {
            if(ac.cnt[i] > best) best = ac.cnt[i];
        }
        printf("%d\n",best);
        for(int i=1; i<=n; i++)
        {
            if(ac.cnt[ms[string(p[i])]] == best) printf("%s\n",p[i]);
        }
    }
    return 0;
}