ZOJ 3933 Team Formation

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;

const int maxn=500+10;
int n;
int belong[maxn];
int cost[maxn];
int g[maxn][maxn];
char str[maxn];

const int INF=0x7FFFFFFF;
struct Edge
{
    int from,to,cap,flow,cost;
};
int N,M,K,len,s,t;
vector<Edge> edges;
vector<int> G[maxn];
int inq[maxn];
int d[maxn];
int p[maxn];
int a[maxn];
int use[maxn];
int dis[maxn][maxn];

void init()
{
    for(int i=0; i<maxn; i++) G[i].clear();
    edges.clear();
}

void Addedge(int from,int to,int cap,int cost)
{
    edges.push_back((Edge)
    {
        from,to,cap,0,cost
    });
    edges.push_back((Edge)
    {
        to,from,0,0,-cost
    });
    len=edges.size();
    G[from].push_back(len-2);
    G[to].push_back(len-1);
}

bool BellmanFord(int s,int t,int &flow,int &cost)
{

    for(int i=0; i<maxn; i++) d[i]=INF;

    memset(inq,0,sizeof(inq));
    memset(p,-1,sizeof(p));

    d[s]=0;
    inq[s]=1;
    p[s]=0;
    a[s]=INF;

    queue<int>Q;
    Q.push(s);
    while(!Q.empty())
    {
        int u=Q.front();
        Q.pop();
        inq[u]=0;
        for(int i=0; i<G[u].size(); i++)
        {
            Edge& e=edges[G[u][i]];
            if(e.cap>e.flow&&d[e.to]>d[u]+e.cost)
            {
                d[e.to]=d[u]+e.cost;
                p[e.to]=G[u][i];
                a[e.to]=min(a[u],e.cap-e.flow);
                if(!inq[e.to])
                {
                    Q.push(e.to);
                    inq[e.to]=1;
                }
            }
        }
    }
    if(d[t]==INF) return false;
    flow+=a[t];
    cost+=d[t]*a[t];
    int u=t;
    while(u!=s)
    {
        edges[p[u]].flow+=a[t];
        edges[p[u]^1].flow-=a[t];
        u=edges[p[u]].from;
    }
    return true;
}

void Mincost (int s,int t)
{
    int flow=0,cost=0;
    while(BellmanFord(s,t,flow,cost));
    printf("%d ",flow);
    printf("%d\n",2*flow-cost);
}

void read()
{
    scanf("%s",str);
    for(int i=0;str[i];i++) belong[i+1]=str[i]-‘0‘;
    scanf("%s",str);
    for(int i=0;str[i];i++) cost[i+1]=str[i]-‘0‘;

    memset(g,0,sizeof g);

    for(int i=1;i<=n;i++)
    {
        int num; scanf("%d",&num);
        while(num--)
        {
            int id; scanf("%d",&id);
            g[i][id]=g[id][i]=1;
        }
    }
}

int main()
{
    int T; scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n); s=0,t=n+1;
        init();
        read();
        for(int i=1;i<=n;i++)
        {
            if(belong[i]==0) Addedge(0,i,1,0);
            else Addedge(i,n+1,1,0);
        }

        for(int i=1;i<=n;i++)
        {
            if(belong[i]==1) continue;

            for(int j=1;j<=n;j++)
            {
                if(i==j) continue;
                if(g[i][j]==1) continue;
                if(belong[j]==0) continue;
                Addedge(i,j,1,cost[i]+cost[j]);
            }
        }
        Mincost(s,t);
        for(int i=0;i<edges.size();i=i+2)
        {
            if(edges[i].from==0) continue;
            if(edges[i].to==n+1) continue;
            if(edges[i].flow==0) continue;
            printf("%d %d\n",edges[i].from,edges[i].to);
        }
    }
    return 0;
}