HDU-2778 DNA Sequence（AC自动机）

# include<iostream>
# include<cstdio>
# include<queue>
# include<string>
# include<cstring>
# include<algorithm>
using namespace std;

const int N=1000;

int cnt;
int ch[N*50+5][95];
int f[N*50+5];
int val[N*50+5];
char p[N][55];
int num[N+5];
char str[N*N*10+5];

void init()
{
	cnt=0;
	memset(ch,0,sizeof(ch));
	memset(val,0,sizeof(val));
	memset(num,0,sizeof(num));
}

int idx(char c)
{
	return (int)(c-32);
}

void insert(char *s,int id)
{
	int r=0;
	int m=strlen(s);
	for(int i=0;i<m;++i){
		int c=idx(s[i]);
		if(!ch[r][c]) ch[r][c]=++cnt;
		r=ch[r][c];
	}
	val[r]=id;
}

void getFail()
{
	queue<int>q;
	f[0]=0;
	for(int i=0;i<95;++i){
		int u=ch[0][i];
		if(u){
			f[u]=0;
			q.push(u);
		}
	}
	while(!q.empty())
	{
		int r=q.front();
		q.pop();
		for(int i=0;i<95;++i){
			if(ch[r][i]){
				f[ch[r][i]]=ch[f[r]][i];
				q.push(ch[r][i]);
			}else ch[r][i]=ch[f[r]][i];
		}
	}
}

void ac(char *str)
{
	int j=0;
	int len=strlen(str);
	for(int i=0;i<len;++i){
		j=ch[j][idx(str[i])];
		int u=j;
		while(u){
			if(val[u]) ++num[val[u]];
			u=f[u];
		}
	}
}

int main()
{
	int n;
	while(~scanf("%d",&n))
	{
		init();
		for(int i=0;i<n;++i){
			cin>>p[i];
			insert(p[i],i+1);
		}
		getFail();
		scanf("%s",str);
		ac(str);
		for(int i=1;i<=n;++i) if(num[i]>0)
			printf("%s: %d\n",p[i-1],num[i]);
	}
	return 0;
}