bzoj 1688: [Usaco2005 Open]Disease Manangement 疾病管理 dfs

题意

分析

代码

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#define N 2005
using namespace std;

int a
,n,d,k,now,ans;

void dfs(int x,int y)
{
if (x>d||y==k)
{
int s=0;
for (int i=1;i<=n;i++)
if ((a[i]|now)==now) s++;
ans=max(ans,s);
return;
}
dfs(x+1,y);
now+=1<<(x-1);
dfs(x+1,y+1);
now-=1<<(x-1);
}

int main()
{
scanf("%d%d%d",&n,&d,&k);
for (int i=1;i<=n;i++)
{
int x;
scanf("%d",&x);
for (int j=1;j<=x;j++)
{
int y;
scanf("%d",&y);
a[i]|=1<<(y-1);
}
}
dfs(1,0);
printf("%d",ans);
return 0;
}