洛谷P3254 圆桌问题 网络流_二分图

Code:

#include<cstdio>
#include<algorithm>
#include<vector>
#include<queue>
#include<cstring>
using namespace std;
const int maxn=1004;
const int INF=10000000;
# define  pb push_back
int s,t;
struct Edge{
	int from,to,cap;
	Edge(int u,int v,int c):from(u),to(v),cap(c) {}
};
vector<Edge>edges;
vector<int>G[maxn];
struct Dicnic{
   int d[maxn],vis[maxn],cur[maxn];
   queue<int>Q;
   void addedge(int u,int v,int c){
   	edges.pb(Edge(u,v,c));               //正向弧
   	edges.pb(Edge(v,u,0));               //反向弧
   	int m=edges.size();
   	G[u].pb(m-2);
   	G[v].pb(m-1);
   }
   int BFS()
   {
    memset(vis,0,sizeof(vis));
    d[s]=0,vis[s]=1;Q.push(s);
    while(!Q.empty()){
    	int u=Q.front();Q.pop();
    	int sz=G[u].size();
    	for(int i=0;i<sz;++i){
    		Edge e=edges[G[u][i]];
    		if(!vis[e.to]&&e.cap>0){
    			d[e.to]=d[u]+1,vis[e.to]=1;
    			Q.push(e.to);
    		}
    	}
    }
    return vis[t];
   }
   int dfs(int x,int a){
       if(x==t)return a;
       int sz=G[x].size();
       int f,flow=0;
       for(int i=0;i<sz;++i){
       	Edge e=edges[G[x][i]];
          cur[x]=i;
       	if(d[e.to]==d[x]+1&&e.cap>0){
       		f=dfs(e.to,min(a,e.cap));
       		if(f)
       		{
       	      int u=G[x][i];
       	      a-=f;
                edges[u].cap-=f;
                edges[u^1].cap+=f;
                flow+=f;
                if(a==0)break;
       		}
       	}
       }
       return flow;
   }
   int maxflow(){
   	int ans=0;
   	while(BFS()){
      memset(cur,0,sizeof(cur));
      ans+=dfs(s,INF);
   	}
   	return ans;
   }
}op;
int main()
{
	int m,n,sum=0;
	scanf("%d%d",&m,&n);
	s=0,t=m+n+1;
     for(int i=1;i<=m;++i)
     {
     	    int a;scanf("%d",&a);
     	    op.addedge(s,i,a);
     	    sum+=a;
     	    for(int j=m+1;j<=m+n;++j)op.addedge(i,j,1);
     }
     for(int i=1;i<=n;++i)
     	{
         int a;scanf("%d",&a);
         op.addedge(i+m,t,a);
     	}
     	int F=op.maxflow();
     if(F!=sum){printf("0\n");return 0;}
     printf("1\n");
     for(int u=1;u<=m;++u)
     {
     	    int sz=G[u].size();
     	    for(int i=0;i<sz;++i)
     	    {
     	    	int e=G[u][i];
     	    	if(e%2==0&&edges[e].cap==0)printf("%d ",edges[e].to-m);
     	    }
     	    printf("\n");
     }
     return 0;
}