最小/大费用最大流

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;

const int maxN=300;
const int maxM=maxN*maxN*4;
const int inf=2147483647;

class Edge
{
public:
    int u,v,cost,flow;
};

int n;
int cnt=-1;
int Head[maxN];
int Next[maxM];
Edge E[maxM];
int Dist[maxN];
bool inqueue[maxN];
int Q[maxM];
int Path[maxN];
int Flow[maxN];
int G[maxN][maxN];

void Add_Edge(int u,int v,int cost,int flow);
bool spfa1();
bool spfa2();

int main()
{
    scanf("%d",&n);
    for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
            scanf("%d",&G[i][j]);
    //Q1最小费用最大流
    cnt=-1;
    memset(Head,-1,sizeof(Head));
    for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
            Add_Edge(i,j+n,G[i][j],1);
    for (int i=1;i<=n;i++)
    {
        Add_Edge(0,i,0,1);
        Add_Edge(i+n,n*2+1,0,1);
    }
    int Ans=0;
    while (spfa1())
    {
        int now=n*2+1;
        int last=Path[now];
        while (now!=0)
        {
            E[last].flow-=Flow[n*2+1];
            E[last^1].flow+=Flow[n*2+1];
            now=E[last].u;
            last=Path[now];
        }
        Ans+=Dist[n*2+1]*Flow[n*2+1];
    }
    cout<<Ans<<endl;
    //Q2最大费用最大流
    cnt=-1;
    memset(Head,-1,sizeof(Head));
    for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
            Add_Edge(i,j+n,G[i][j],1);
    for (int i=1;i<=n;i++)
    {
        Add_Edge(0,i,0,1);
        Add_Edge(i+n,n*2+1,0,1);
    }
    Ans=0;
    while (spfa2())
    {
        int now=n*2+1;
        int last=Path[now];
        while (now!=0)
        {
            E[last].flow-=Flow[n*2+1];
            E[last^1].flow+=Flow[n*2+1];
            now=E[last].u;
            last=Path[now];
        }
        Ans+=Dist[n*2+1]*Flow[n*2+1];
    }
    cout<<Ans<<endl;
    return 0;
}

void Add_Edge(int u,int v,int cost,int flow)
{
    cnt++;
    Next[cnt]=Head[u];
    Head[u]=cnt;
    E[cnt].u=u;
    E[cnt].v=v;
    E[cnt].cost=cost;
    E[cnt].flow=flow;

    cnt++;
    Next[cnt]=Head[v];
    Head[v]=cnt;
    E[cnt].u=v;
    E[cnt].v=u;
    E[cnt].flow=0;
    E[cnt].cost=-cost;
}

bool spfa1()
{
    for (int i=0;i<=n*2+1;i++)
        Dist[i]=inf;
    memset(inqueue,0,sizeof(inqueue));
    int h=1,t=0;
    Q[1]=0;
    inqueue[0]=1;
    Dist[0]=0;
    Flow[0]=inf;
    do
    {
        t++;
        int u=Q[t];
        inqueue[u]=0;
        for (int i=Head[u];i!=-1;i=Next[i])
        {
            int v=E[i].v;
            if ((E[i].flow>0)&&(Dist[v]>Dist[u]+E[i].cost))
            {
                Dist[v]=Dist[u]+E[i].cost;
                Flow[v]=min(Flow[u],E[i].flow);
                Path[v]=i;
                if (inqueue[v]==0)
                {
                    h++;
                    Q[h]=v;
                    inqueue[v]=1;
                }
            }
        }
    }
    while (h!=t);
    if (Dist[n*2+1]==inf)
        return 0;
    return 1;
}

bool spfa2()
{
    for (int i=0;i<=n*2+1;i++)
        Dist[i]=-inf;
    memset(inqueue,0,sizeof(inqueue));
    int h=1,t=0;
    Q[1]=0;
    inqueue[0]=1;
    Dist[0]=0;
    Flow[0]=inf;
    do
    {
        t++;
        int u=Q[t];
        inqueue[u]=0;
        for (int i=Head[u];i!=-1;i=Next[i])
        {
            int v=E[i].v;
            if ((E[i].flow>0)&&(Dist[v]<Dist[u]+E[i].cost))
            {
                Dist[v]=Dist[u]+E[i].cost;
                Flow[v]=min(Flow[u],E[i].flow);
                Path[v]=i;
                if (inqueue[v]==0)
                {
                    h++;
                    Q[h]=v;
                    inqueue[v]=1;
                }
            }
        }
    }
    while (h!=t);
    if (Dist[n*2+1]==-inf)
        return 0;
    return 1;
}