【题目】http://poj.org/problem?id=2226

【代码】

#include<cstdio>
#include<cstring>
const int M=1005;

int mp[M][M]= {0}, vis[M], used[M]={0};
char mp2[M][M];
int a[M][M], b[M][M];
int m, n, x, y;

bool Find(int u)
{
    for(int i = 1 ; i <= y ; i++)
    {
        if(!vis[i] && mp[u][i])
        {
            vis[i] = 1;
            if(!used[i] || Find(used[i]))
            {
                used[i] = u;
                return true;
            }
        }
    }
    return false;
}
void Build()//构图
{
    x = y = 0;
    memset(a, 0, sizeof(a));
    memset(b, 0, sizeof(b));
    for(int i = 1 ; i <= m ; i++)
    {
        for(int j = 1 ; j <= n ; j++)
        {
            if(mp2[i][j] == '*')
            {
                if(mp2[i][j - 1] == '*')
                    a[i][j] = a[i][j - 1];
                else
                    a[i][j] = ++x;
            }
        }
    }//木板横着放
    for(int i = 1 ; i <= m ; i++)
    {
        for(int j = 1 ; j <= n ; j++)
        {
            if(mp2[i][j] == '*')
            {
                if(mp2[i - 1][j] == '*')
                    b[i][j] = b[i - 1][j];
                else
                    b[i][j] = ++y;
                mp[a[i][j]][b[i][j]] = 1;
            }
        }
    }//木板竖着放
}

int main()
{
    int ans=0;
    scanf("%d%d", &m, &n);
    for(int i = 1 ; i <= m ; i++)
    {
        getchar();
        for(int j = 1 ; j <= n ; j++)
        {
            scanf("%c", &mp2[i][j]);
        }
    }
    Build();
    for(int i = 1 ; i <= x ; i++)
    {
        memset(vis, 0, sizeof(vis));
        if(Find(i))
            ans++;
    }
    printf("%d\n", ans);
}