POJ 2441 Arrange the Bulls 状态DP

//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<sstream>
#include<cmath>
#include<climits>
#include<string>
#include<map>
#include<queue>
#include<vector>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define pb(a) push(a)
#define INF 0x1f1f1f1f
#define lson idx<<1,l,mid
#define rson idx<<1|1,mid+1,r
#define PI  3.1415926535898
template<class T> T min(const T& a,const T& b,const T& c) {
    return min(min(a,b),min(a,c));
}
template<class T> T max(const T& a,const T& b,const T& c) {
    return max(max(a,b),max(a,c));
}
void debug() {
#ifdef ONLINE_JUDGE
#else

    freopen("d:\in1.txt","r",stdin);
    freopen("d:\out1.txt","w",stdout);
#endif
}
int getch() {
    int ch;
    while((ch=getchar())!=EOF) {
        if(ch!=' '&&ch!='
')return ch;
    }
    return EOF;
}

int dp[1<<20];
int like[22][22];
int n,m;
int f()
{
    dp[0]=1;
    for(int i=1;i<=n;i++)
    {
        for(int st=(1<<m)-1;st>=0;st--) if(dp[st]!=0)
        {
            for(int j=0;j<m;j++) if(like[i][j]&&!((1<<j)&st))
            {
                dp[st|(1<<j)]+=dp[st];
                //printf("dp[%d]=%d
",st|(1<<j),dp[st|(1<<j)]);
            }

            dp[st]=0;
        }
    }
    int ans=0;
    for(int st=0;st<(1<<m);st++)
        if(dp[st]!=-1)ans+=dp[st];
    return ans;
}
int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        memset(like,0,sizeof(like));
        memset(dp,0,sizeof(dp));
        for(int i=1;i<=n;i++)
        {
            int p;
            scanf("%d",&p);
            for(int j=1;j<=p;j++)
            {
                int x;
                scanf("%d",&x);
                like[i][x-1]=1;
            }
        }
        int res=f();
        printf("%d
",res);
    }
    return 0;
}