SRM494 500pt

// 2nd problem in SRM494
//Could u tell it's TIME LIMIT EXCEEDED?!


import java.util.*;
import java.util.regex.*;
import java.text.*;
import java.math.*;


public class Painting
{
    public int largestBrush(String[] p)
    {
        boolean pass[]=new boolean[501];
        int i,j,k;
        int g[][]=new int[51][51];
        for(i=0;i<p.length;i++)
        {
            for(j=0;j<p[i].length();j++)
            {
                g[i][j]=0;
                if(i>0)
                    g[i][j]+=g[i-1][j];
                if(j>0)
                    g[i][j]+=g[i][j-1];
                if( j>0 && i>0)
                    g[i][j]-=g[i-1][j-1];
                if(p[i].charAt(j)=='B') g[i][j]++;
            //  System.out.print(g[i][j]+" ");
            }
        //  System.out.println();
        }
        System.out.println("\n\n");

        int res=1,t;
        Arrays.fill(pass,true);
        for(k=0;k<p.length;k++)
        {
            for(i=0;i+k<p.length;i+=k)
            {
                for(j=0;j+k<p[i].length();j+=k)
                {
                    t=g[i+k][j+k];
                    if(i>0)
                        t-=g[i-1][j+k];
                    if(j>0)
                        t-=g[i+k][j-1];
                    if(i>0 && j>0)
                     t+=g[i-1][j-1];
                    if( t  !=(k+1)*(k+1))
                        pass[k+1]=false;
                }
            }
        }
        for(i=p.length;i>0;i--)
            if(pass[i]) return i;
        return 1;
    }

<%:testing-code%>
}
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