最小费用最大流模板

poj2195

/*
POJ 2195 Going Home
邻接表形式最小费用最大流
*/
#include
#include
#include
#include
#include
using namespace std;

const int MAXN=1000;
const int MAXE=100000;
const int INF=0x3f3f3f3f;
struct Edge
{
    int from;
    int to;
    int next;
    int re;//记录逆边的下标
    int cap;//容量
    int cost;//费用
}edge[MAXE];
int pre[MAXN];
int head[MAXN];
bool vis[MAXN];
int que[MAXN];
int dist[MAXN];
int tol;//边的总数
void add(int u,int v,int ca,int co)
{
    edge[tol].from=u;
    edge[tol].to=v;
    edge[tol].cap=ca;
    edge[tol].cost=co;
    edge[tol].re=tol+1;
    edge[tol].next=head[u];
    head[u]=tol++;

    edge[tol].from=v;//加逆边
    edge[tol].to=u;
    edge[tol].cap=0;
    edge[tol].cost=-co;
    edge[tol].re=tol-1;
    edge[tol].next=head[v];
    head[v]=tol++;
}
int n;
int start;
int end;
bool SPFA()
{
    int front=0,rear=0;
    for(int v=0;v<=n;v++)
    {
        if(v==start)
        {
            que[rear++]=v;
            vis[v]=true;
            dist[v]=0;
        }
        else
        {
            dist[v]=INF;
            vis[v]=false;
        }
    }
    while(front!=rear)
    {
        int u=que[front++];
        vis[u]=false;
        if(front>=MAXN)front=0;
        for(int i=head[u];i!=-1;i=edge[i].next)
        {
            int v=edge[i].to;
            if(edge[i].cap&&dist[v]>dist[u]+edge[i].cost)
            {
                dist[v]=dist[u]+edge[i].cost;
                pre[v]=i;
                if(!vis[v])
                {
                    que[rear++]=v;
                    vis[v]=true;
                    if(rear>=MAXN)rear=0;
                }
            }
        }
    }
    if(dist[end]==INF)return false;
    return true;
}
int c;//费用
int f;//最大流

void minCostMaxflow()
{
    c=f=0;
    int u,p;
    while(SPFA())
    {
        int Min=INF;
        for(u=end;u!=start;u=edge[p].from)
        {
            p=pre[u];
            Min=min(Min,edge[p].cap);
        }
        for(u=end;u!=start;u=edge[p].from)
        {
            p=pre[u];
            edge[p].cap-=Min;
            edge[edge[p].re].cap+=Min;

        }
        c+=dist[end]*Min;
        f+=Min;
    }
}
struct Node
{
    int x,y;
};
Node node1[MAXN],node2[MAXN];
char str[MAXN][MAXN];
int main()
{
   // freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    int N,M;
    while(scanf("%d%d",&N,&M))
    {
        if(N==0&&M==0)break;
        int tol1=0,tol2=0;
        for(int i=0;i