AC日记——Dining poj 3281

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define maxn 2005
#define INF 0x7fffffff

int n,f,d,s,t,head[maxn],E[maxn<<2],V[maxn<<2],F[maxn<<2];
int cnt=1,deep[maxn],que[maxn<<4];

inline void in(int &now)
{
    char Cget=getchar();now=0;
    while(Cget>‘9‘||Cget<‘0‘) Cget=getchar();
    while(Cget>=‘0‘&&Cget<=‘9‘)
    {
        now=now*10+Cget-‘0‘;
        Cget=getchar();
    }
}

inline void edge_add(int u,int v,int f)
{
    E[++cnt]=head[u],V[cnt]=v,F[cnt]=f,head[u]=cnt;
    E[++cnt]=head[v],V[cnt]=u,F[cnt]=0,head[v]=cnt;
}

inline bool bfs()
{
    for(int i=s;i<=t;i++) deep[i]=-1;
    int h=0,tail=1;deep[s]=0,que[h]=s;
    while(h<tail)
    {
        int now=que[h++];
        for(int i=head[now];i;i=E[i])
        {
            if(deep[V[i]]<0&&F[i]>0)
            {
                deep[V[i]]=deep[now]+1;
                if(V[i]==t) return true;
                que[tail++]=V[i];
            }
        }
    }
    return false;
}

int flowing(int now,int flow)
{
    if(flow<=0||now==t) return flow;
    int oldflow=0;
    for(int i=head[now];i;i=E[i])
    {
        if(F[i]>0&&deep[V[i]]==deep[now]+1)
        {
            int pos=flowing(V[i],min(flow,F[i]));
            flow-=pos,oldflow+=pos,F[i]-=pos,F[i^1]+=pos;
            if(flow==0) return oldflow;
        }
    }
    if(oldflow==0) deep[now]=-1;
    return oldflow;
}

int main()
{
    in(n),in(f),in(d);
    int u,v,nf,nd;t=f+n+n+d+1;
    for(int i=1;i<=f;i++) edge_add(s,i,1);
    for(int i=1;i<=d;i++) edge_add(f+n+n+i,t,1);
    for(int i=1;i<=n;i++)
    {
        edge_add(f+i,f+n+i,1),in(nf),in(nd);
        for(int j=1;j<=nf;j++) in(u),edge_add(u,f+i,1);
        for(int j=1;j<=nd;j++) in(u),edge_add(f+n+i,f+n+n+u,1);
    }
    int ans=0;
    while(bfs()) ans+=flowing(s,INF);
    cout<<ans;
    return 0;
}