poj 2226（最小点覆盖集）

嘛。。稍微有一点变形，相当于每隔一段草，一行或一列就成新的了，用rnum，cnum记录一下就好了。

# include <cstdio>
# include <cstring>
# include <algorithm>
# include <iostream>
using namespace std;
char map[100][100];
int mp[500][500],f[500],flag[500],r,c,sum,rnum,cnum,maxn,col[100][100];
int find(int i)
{
    int j;
    for (j=1;j<=cnum;++j)
    {
        if (mp[i][j]&&!flag[j])
        {
            flag[j] = 1;
            if (!f[j]||find(f[j]))
            {
                f[j] = i;
                return 1;
            }
        }
    }
    return 0;
}
int main()
{
    int i,j;
    char str[100];
    while (~scanf("%d%d",&r,&c))
    {
        sum = 0;rnum = 1;cnum = c;
        memset(mp,0,sizeof(mp));
        memset(f,0,sizeof(f));
        for (i=1;i<=r;++i)
        {
            scanf("%s",str+1);
            for (j=1;j<=c;++j)
            {
                map[i][j] = str[j];
                if (str[j]=='*')
                {
                    if (map[i][j-1] == '.')
                        ++rnum;
                    if (i==1)
                        col[i][j] = j;
                    else if (map[i-1][j] == '.')
                        col[i][j] = (++cnum);
                    else
                        col[i][j] = col[i-1][j];
                    mp[rnum][col[i][j]] = 1;
                }
            }
            rnum++;
        }
        for (i=1;i<=rnum;++i)
        {
            memset(flag,0,sizeof(flag));
            sum += find(i);
        }
        printf("%d\n",sum);
    }
    return 0;
}