[Explanations] P2763 test database problem (network flow)

P2763 test database problem

Consider an answer to the questions to be added into a collection of what conditions?

• Some type
• Counted only once

And restrictions on both, so we connect "type point" and "point of action" with a serial manner.

Judgment no solution to determine whether full capacity. Output scheme on a flow output side of the end.

//@winlere
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>

using namespace std;  typedef long long ll;
inline int qr(){
      register int ret=0,f=0;
      register char c=getchar();
      while(c<48||c>57)f|=c==45,c=getchar();
      while(c>=48&&c<=57) ret=ret*10+c-48,c=getchar();
      return f?-ret:ret;
}

const int inf=0x3f3f3f3f;
const int maxn=1.9e3+5;
int nodecnt;
struct E{
      int to,nx,w;
}e[50005];
int head[maxn];
int cur[maxn];
int d[maxn];
int cnt=-1,S,T,n,m,k;
vector< int > ve[maxn];
inline void add(const int&fr,const int&to,const int&w,const int&f){
      //printf("fr=%d to=%d w=%d cnt=%d\n",fr,to,w,cnt);      
      e[++cnt]={to,head[fr],w};
      head[fr]=cnt;
      if(f)add(to,fr,0,0);
}
queue< int >q;
inline bool bfs(){
      for(register int t=1;t<=n+k+2;++t) cur[t]=head[t],d[t]=0;
      q.push(S);
      d[S]=1;
      while(!q.empty()){
        register int now=q.front();
        q.pop();
        if(now==T)continue;
        for(register int t=head[now];t!=-1;t=e[t].nx){
          if(!d[e[t].to]&&e[t].w>0){
            d[e[t].to]=d[now]+1;
            q.push(e[t].to);
          }
        }
      }
      return d[T];
}

int dfs(const int&now,const int&last,int fl){
      if(now==T||fl==0)return fl;
      register int ret=0;
      for(register int&t=cur[now];t!=-1;t=e[t].nx){
        if(e[t].w>0&&d[e[t].to]==d[now]+1&&fl){
          int d=dfs(e[t].to,now,min(fl,e[t].w));
          e[t].w-=d;e[t^1].w+=d;ret+=d;fl-=d;
        }
      }
      return ret;
}

inline int dinic(){
      register int ret=0;
      while(bfs()) ret+=dfs(S,0,inf);
      return ret;
}

int main(){
      freopen("testlib.in","r",stdin);
      freopen("testlib.out","w",stdout);
      memset(head,-1,sizeof head);
      k=qr();n=qr();
      S=1;T=k+n+2;
      for(register int t=1;t<=k;++t)
        add(S,t+1,qr(),1);
      for(register int t=1,t1;t<=n;++t){
        t1=qr();
        for(register int i=1;i<=t1;++i)
          add(qr()+1,t+k+1,1,1);
        add(t+k+1,T,1,1);
      }
      dinic();
      int ok=1;
      for(register int t=head[S];t!=-1;t=e[t].nx)
        if(e[t].w) ok=0;
      if(ok) {
        //printf("%d\n",f);
        for(register int now=2;now<=k+1;++now){
          printf("i:%d ",now-1);
          for(register int t=head[now];t!=-1;t=e[t].nx)
            if(e[t].to!=1&&e[t].w==0)
                  printf("%d ",e[t].to-k-1);
          putchar('\n');
        }
      }
      else puts("No Solution!");
      return 0;
}