poj2195

题解：

简单KM

把每一个男的和房子分离

代码:

#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
const int NN=1005,MM=10005;
int a[NN][NN],v[NN][NN],g[NN][NN],lk[MM],lx[MM],ly[MM];
int visx[MM],visy[MM],slack[MM],N,M,n,n1,n2,cnt,ans;
int dfs(int x)
{
    visx[x]=cnt;
    for (int y=1;y<=n;y++)
     {
        if (visy[y]==cnt) continue;
        int t=lx[x]+ly[y]-g[x][y];
        if (!t)
         {
             visy[y]=cnt;
            if (!lk[y]||dfs(lk[y])){lk[y]=x;return 1;}
         }
        else if (slack[y]>t) slack[y]=t;
     }
    return 0;
}
void KM()
{
    memset(lk,0,sizeof(lk));
    memset(lx,0,sizeof(lx));
    memset(ly,0,sizeof(ly));
    for (int i=1;i<=n;i++)
     for (int j=1;j<=n;j++)lx[i]=max(lx[i],g[i][j]);
    for (int x=1;x<=n;++x)
     {
        for (int i=1;i<=n;i++)slack[i]=1e9;
        while (cnt++,!dfs(x))
         {
            int d=1e9;
            for (int i=1;i<=n;i++)
             if (visy[i]!=cnt) d=min(d,slack[i]);
            for (int i=1;i<=n;i++)
             {
                if (visx[i]==cnt) lx[i]-=d;
                if (visy[i]==cnt) ly[i]+=d;
                else slack[i]-=d;
             }
          }
     }
    return;
}
void work()
{
    n1=n2=ans=0;
    for (int i=1;i<=N;i++)
     for (int j=1;j<=M;j++)
      {
        for (a[i][j]=getchar();a[i][j]!='.'&&a[i][j]!='m'&&a[i][j]!='H';a[i][j]=getchar());
        if (a[i][j]=='m') v[i][j]=++n1;
        if (a[i][j]=='H') v[i][j]=++n2;
     }
    for (int i=1;i<=N;i++)
     for (int j=1;j<=M;++j)
      {
        if (a[i][j]!='m') continue;
        for (int p=1;p<=N;p++)
         for (int q=1;q<=M;q++)
            if (a[p][q]=='H') g[v[i][j]][v[p][q]]=-abs(i-p)-abs(j-q);
      }
    n=n1;
    KM();
    for (int i=1;i<=n;i++)ans+=lx[i]+ly[i];
    printf("%d
",-ans);
    return;
}
int main()
{
    while (~scanf("%d%d",&N,&M)&&N|M) work();
    return 0;
}