uva 11825

刘书上例题  关于集合的动态规划

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <vector>
#include <sstream>
#include <string>
#include <cstring>
#include <algorithm>
#include <iostream>
#define maxn 200010
#define INF 0x7fffffff
#define inf 10000000
#define MOD 1000000007
#define ull unsigned long long
#define ll long long
using namespace std;

int p[20], f[maxn], s[maxn], n;

void init()
{
    for(int i = 0; i < n; ++ i)
    {
        p[i] = 1 << i;
        int m, x;
        scanf("%d", &m);
        while(m --)
        {
            scanf("%d", &x);
            p[i] |= (1 << x);
        }
    }
    for(int S = 1; S < (1 << n); ++ S)
    {
        s[S] = 0;
        for(int i = 0; i < n; ++ i) if(S & (1 << i)) s[S] |= p[i];
    }
}
int main()
{
    int ca = 0;
    while(scanf("%d", &n) == 1 && n)
    {
        init();
        int all = (1 << n) - 1;
        f[0] = 0;
        for(int i = 1; i < (1 << n); ++ i)
        {
            f[i] = 0;
            for(int S = i; S; S = i&(S-1))
                if(s[S] == all) f[i] = max(f[i], f[i^S]+1);
        }
        printf("Case %d: %d\n", ++ ca, f[all]);
    }
    return 0;
}