Gym

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=2050;
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,0));
        edges.push_back(Edge(to,from,0,0));
        m=edges.size();
        G[from].push_back(m-2);
        G[to].push_back(m-1);
    }
    bool BFS()
    {
        memset(vis,0,sizeof(vis));
        queue<int> Q;
        Q.push(s);
        d[s]=0;
        vis[s]=1;
        while(!Q.empty())
        {
            int x=Q.front();
            Q.pop();
            for(int i=0;i<G[x].size();i++)
            {
                Edge& e=edges[G[x][i]];
                if(!vis[e.to]&&e.cap>e.flow)
                {
                    vis[e.to]=1;
                    d[e.to]=d[x]+1;
                    Q.push(e.to);
                }
            }
        }
        return vis[t];
    }
    int DFS(int x,int a)
    {
        if(x==t||a==0) return a;
        int flow=0,f;
        for(int& i=cur[x];i<G[x].size();i++)
        {
            Edge& e=edges[G[x][i]];
            if(d[x]+1==d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>0)
            {
                e.flow+=f;
                edges[G[x][i]^1].flow-=f;
                flow+=f;
                a-=f;
                if(a==0) break;
            }
        }
        return flow;
    }
    int Maxflow(int s,int t)
    {
        this->s=s;this->t=t;
        int flow=0;
        while(BFS())
        {
            memset(cur,0,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=1;i<=n;i++)
    {
        fuck.AddEdge(0,i+1,1);
        fuck.AddEdge(1,i+1,1);
    }
    fuck.AddEdge(0,1,k);
    for(i=1;i<=n;i++)
    {
        scanf("%d",&tmpn);
        for(j=1;j<=tmpn;j++)
        {
            scanf("%d",&x);
            fuck.AddEdge(i+1,n+1+x,1);
        }
    }
    for(i=1;i<=m;i++)
        fuck.AddEdge(n+1+i,n+m+2,1);
    printf("%d
",fuck.Maxflow(0,n+m+2));
    return 0;
}