UVA 10779 （最大流)

#include "cstdio"
#include "vector"
#include "cstring"
#include "queue"
using namespace std;
#define maxn 405
#define inf 100000000
struct Edge
{
    int from,to,cap,flow;
    Edge(int FROM,int TO,int CAP,int FLOW):from(FROM),to(TO),cap(CAP),flow(FLOW) {}
};
int d[maxn],p[maxn],gap[maxn],cur[maxn],paste[15][30];
bool vis[maxn];
vector<int> G[maxn];
vector<Edge> edges;
void addedge(int from,int to,int cap)
{
    edges.push_back(Edge(from,to,cap,0));
    edges.push_back(Edge(to,from,0,0));
    int m=edges.size();
    G[from].push_back(m-2);
    G[to].push_back(m-1);
}
void bfs(int s,int t)
{
    memset(vis,false,sizeof(vis));
    memset(d,0,sizeof(d));
    memset(p,0,sizeof(p));
    d[t]=0;vis[t]=true;
    queue<int> Q;Q.push(t);
    while(!Q.empty())
    {
        int u=Q.front();Q.pop();
        for(int v=0;v<G[u].size();v++)
        {
            Edge e=edges[G[u][v]^1];
            if(!vis[e.from]&&e.cap>e.flow)
            {
                vis[e.from]=true;
                d[e.from]=d[u]+1;
                Q.push(e.from);
            }
        }
    }
}
int augment(int s,int t)
{
    int x=t,a=inf;
    while(x!=s)
    {
        Edge e=edges[p[x]];
        a=min(a,e.cap-e.flow);
        x=e.from;
    }
    x=t;
    while(x!=s)
    {
        edges[p[x]].flow+=a;
        edges[p[x]^1].flow-=a;
        x=edges[p[x]].from;
    }
    return a;
}
int maxflow(int s,int t)
{
    int flow=0,u=s;
    bfs(s,t);
    memset(gap,0,sizeof(gap));
    memset(cur,0,sizeof(cur));
    for(int i=0;i<=t;i++) gap[d[i]]++;
    while(d[s]<t+1)
    {
        if(u==t)
        {
            flow+=augment(s,t);
            u=s;
        }
        bool flag=false;
        for(int v=cur[u];v<G[u].size();v++) //Advance
        {
            Edge e=edges[G[u][v]];
            if(e.cap>e.flow&&d[u]==d[e.to]+1)
            {
                flag=true;
                p[e.to]=G[u][v];
                cur[u]=v;
                u=e.to;
                break;
            }
        }
        if(!flag) //Retreat
        {
            int m=t+1;
            for(int v=0;v<G[u].size();v++)
            {
                Edge e=edges[G[u][v]];
                if(e.cap>e.flow) m=min(m,d[e.to]);
            }
            if(--gap[d[u]]==0) break;
            gap[d[u]=m+1]++;
            cur[u]=0;
            if(u!=s) u=edges[p[u]].from;
        }
    }
    return flow;
}
int main()
{
    int T,n,k,id,num,no=0;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d",&n,&k);
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&num);
            for(int j=1;j<=num;j++)
            {
                scanf("%d",&id);
                paste[i][id]++;
            }
        }
        for(int i=1;i<=k;i++) //S->Bob
            if(paste[1][i]) {addedge(0,i,paste[1][i]);}
        for(int i=2;i<=n;i++) //Bob->friends
            for(int j=1;j<=k;j++)
            {
                if(paste[i][j]>=2) addedge(k+i,j,paste[i][j]-1);
                if(!paste[i][j]) addedge(j,k+i,1);
            }
        for(int i=1;i<=k;i++) addedge(i,k+n+1,1);//Bob->T
        printf("Case #%d: %d\n",++no,maxflow(0,k+n+1));
        for(int i=0;i<maxn;i++) G[i].clear();
        edges.clear();
        memset(paste,0,sizeof(paste));
    }
}