Gym - 101981I The 2018 ICPC Asia Nanjing Regional Contest I.Magic Potion 最大流

题面

题意:n个英雄,m个怪兽,第i个英雄可以打第i个集合里的一个怪兽,一个怪兽可以在多个集合里,有k瓶药水,每个英雄最多喝一次,可以多打一只怪兽,求最多打多少只 n,m,k<=500

题解:显然的最大流裸题,多加一个药水点,药酱入度k,然后再连向英雄

队友抄的模板所以不是我的那个板子

 #include<bits/stdc++.h>
 using namespace std;
 struct Edge
 {
     int from,to,cap,flow;
     Edge(int u,int v,int c,int f)
     {
         from=u;
         to=v;
         cap=c;
         flow=f;
     }
 };
 const int maxn=;
 const int INF=0x3f3f3f3f;
 struct Dinic
 {
     int n,m,s,t;
     vector<Edge> edges;
     vector<int> G[maxn];
     int d[maxn];
     int cur[maxn];
     bool vis[maxn];
     void AddEdge(int from,int to, int cap)
     {
         edges.push_back(Edge(from,to,cap,));
         edges.push_back(Edge(to,from,,));
         m=edges.size();
         G[from].push_back(m-);
         G[to].push_back(m-);
     }
     bool BFS()
     {
         memset(vis,,sizeof(vis));
         queue<int> Q;
         Q.push(s);
         d[s]=;
         vis[s]=;
         while(!Q.empty())
         {
             int x=Q.front();
             Q.pop();
             for(int i=;i<G[x].size();i++)
             {
                 Edge& e=edges[G[x][i]];
                 if(!vis[e.to]&&e.cap>e.flow)
                 {
                     vis[e.to]=;
                     d[e.to]=d[x]+;
                     Q.push(e.to);
                 }
             }
         }
         return vis[t];
     }
     int DFS(int x,int a)
     {
         if(x==t||a==) return a;
         int flow=,f;
         for(int& i=cur[x];i<G[x].size();i++)
         {
             Edge& e=edges[G[x][i]];
             if(d[x]+==d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>)
             {
                 e.flow+=f;
                 edges[G[x][i]^].flow-=f;
                 flow+=f;
                 a-=f;
                 if(a==) break;
             }
         }
         return flow;
     }
     int Maxflow(int s,int t)
     {
         this->s=s;this->t=t;
         int flow=;
         while(BFS())
         {
             memset(cur,,sizeof(cur));
             flow+=DFS(s,INF);
         }
         return flow;
     }
 }fuck;
 int main()
 {
     int  n,m,k,i,j,tmpn,x;
     scanf("%d%d%d",&n,&m,&k);
     for(i=;i<=n;i++)
     {
         fuck.AddEdge(,i+,);
         fuck.AddEdge(,i+,);
     }
     fuck.AddEdge(,,k);
     for(i=;i<=n;i++)
     {
         scanf("%d",&tmpn);
         for(j=;j<=tmpn;j++)
         {
             scanf("%d",&x);
             fuck.AddEdge(i+,n++x,);
         }
     }
     for(i=;i<=m;i++)
         fuck.AddEdge(n++i,n+m+,);
     printf("%d\n",fuck.Maxflow(,n+m+));
     return ;
 }