POJ 2195（二分图最大权匹配）

#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define INF 0x3f3f3f3f
#define MAXN 105

using namespace std;

int n,a[MAXN][MAXN],vx[MAXN],vy[MAXN],lx[MAXN],ly[MAXN],pre[MAXN],slack[MAXN];
int N,M,cnth,cntm;
struct point{
int x,y;
}tmph[MAXN],tmpm[MAXN];
char st[MAXN][MAXN];

bool dfs(int index)
{
vx[index]=1;
for(int i=1;i<=n;i++)
{
if(!vy[i]&&lx[index]+ly[i]==a[index][i])
{
vy[i]=1;
if(!pre[i]||dfs(pre[i]))
{
pre[i]=index;
return 1;
}
}
else if(!vy[i]&&lx[index]+ly[i]>a[index][i])
slack[i]=min(slack[i], lx[index]+ly[i]-a[index][i]);
}
return 0;
}

int KM()
{
memset(ly,0,sizeof(ly));
for(int i=1;i<=n;i++)
{
lx[i]=-INF;
for(int j=1;j<=n;j++)
lx[i]=max(lx[i],a[i][j]);
}

int ans=0,d;
memset(pre,0,sizeof(pre));
for(int i=1;i<=n;i++)
{
memset(slack,INF,sizeof(slack));
while(1)
{
memset(vx,0,sizeof(vx));
memset(vy,0,sizeof(vy));
if(dfs(i))
break;

d=INF;
for(int i=1;i<=n;i++)
if(!vy[i])
d=min(d,slack[i]);

if(d==INF) return -1;           //no matching
for(int j=1;j<=n;j++)
if(vx[j]) lx[j]-=d;
for(int j=1;j<=n;j++)
if(vy[j]) ly[j]+=d;
}
}

for(int i=1;i<=n;i++)
ans+=a[pre[i]][i];
return ans;
}

int main()
{
while(~scanf("%d %d", &N, &M))
{
if(!N&&!M)
break;
cnth=cntm=0;
getchar();
for(int i=1;i<=N;i++)
{
for(int j=1;j<=M;j++)
{
scanf("%c",&st[i][j]);
if(st[i][j]=='m')
cntm++,tmpm[cntm].x=i, tmpm[cntm].y=j;
if(st[i][j]=='H')
cnth++,tmph[cnth].x=i, tmph[cnth].y=j;
}
getchar();
}

n=cntm;
for(int i=1;i<=cntm;i++)
for(int j=1;j<=cnth;j++)
a[i][j]=-(abs(tmpm[i].x-tmph[j].x)+abs(tmpm[i].y-tmph[j].y));

printf("%d\n",-KM());
}

return 0;
}