http://www.cnblogs.com/lonelycatcher/archive/2011/05/27/2060158.html
#include <iostream>
#include <string.h>
#include <cstdio>
using namespace std;
int hash[1<<15];
int main()
{ // freopen("in.txt","r",stdin);
int n,m,k,i,x,y;
while(scanf("%d%d",&n,&m)!=EOF)
{
memset(hash,0,sizeof(hash));
m=1<<m;
while(n--)
{
scanf("%d",&k);
y=0;//开始时y=0写到上面去了,郁闷,
while(k--)
{
scanf("%d",&x);
y=y|(1<<(x-1));
}
hash[y]=1;
for(i=0;i<=m;i++)
if(hash[i])
hash[i|y]=1; //算是得到新集合吧
}n=0;
for(i=0;i<=m;i++)
if(hash[i])
n++;
printf("%d\n",n);
}
return 0;
}