Poj Solution 3051

http://poj.org/problem?id=3051

//* @author: 82638882@163.com
import java.io.*;
public class Main
{
    static int[][] p;
    static int a,b,max=0,cnt;
    public static void main(String[] args) throws IOException
    {
        InputStreamReader is=new InputStreamReader(System.in);
        BufferedReader in=new BufferedReader(is);
        String[] ss=in.readLine().split(" ");
        a=Integer.parseInt(ss[0]);
        b=Integer.parseInt(ss[1]);
        p=new int[b+2][a+2];
        for(int i=1;i<=b;i++)
        {
          for(int j=1;j<=a;j++)
            p[i][j]=in.read();
          in.readLine();
        }
        for(int i=1;i<=b;i++)
        {
          for(int j=1;j<=a;j++)
          {
            cnt=0;
            f(i,j);
            if(cnt>max) max=cnt;
           }
        }
        System.out.println(max);
    }
    static void f(int x,int y)
    {
        if(p[x][y]!='*')return;
        p[x][y]=0;
        cnt++;
        f(x,y+1);
        f(x,y-1);
        f(x+1,y);
        f(x-1,y);
    }
}