hihoCoder 网络流五·最大权闭合子图 (网络流学习#5 记录)

#include<cstdio>
#include<queue>
using namespace std;
const int N=205,M=205,INF=0x3f3f3f3f;
const int maxn=N+M+10;
int b,s=0,t,c[maxn][maxn],dis[maxn],ss;
int n,m;
#define Min(a,b) (a<b)?a:b
int bfs()
{
for(int i=s+1; i<=t; i++)
dis[i]=0;
dis[s]=1;
queue<int>q;
q.push(s);
while(!q.empty())
{
int tmp=q.front();
q.pop();
for(int i=s+1; i<=t; i++)
{
if(c[tmp][i]>0&&!dis[i])
{
dis[i]=dis[tmp]+1;
q.push(i);
}
}
}
return dis[t];
}
int dfs(int x,int v)
{
if(x==t||v==0)
return v;
int ans=0,tmp;
for(int i=s+1; i<=t; i++)
{
if(dis[x]+1==dis[i]&&c[x][i]>0)
{
tmp=dfs(i,Min(v,c[x][i]));
if(tmp<=0)
continue;
ans+=tmp;
v-=tmp;
c[x][i]-=tmp;
c[i][x]+=tmp;
if(v==0)
break;
}
}
return ans;
}
int work()
{
int ans=0;
while(bfs())
{
ans+=dfs(s,INF);
}
return max(ss-ans,0);
}
int main()
{

scanf("%d%d",&n,&m);
t=n+m+1;
ss=0;
for(int i=s; i<=t; i++)
for(int j=s; j<=t; j++)
c[i][j]=0;
for(int i=1; i<=m; i++)
{
scanf("%d",&b);
c[n+i][t]+=b;
}
int a,k,x;
for(int i=1; i<=n; i++)
{
scanf("%d%d",&a,&k);
c[s][i]+=a;
if(a>0)
ss+=a;
for(int j=0; j<k; j++)
{
scanf("%d",&x);
c[i][n+x]=INF;
}
}
printf("%d\n",work());
}