[백준] 1018번 체스판 다시 칠하기 (silver 4

import java.io.*;
import java.util.*;
public class Main{
    static String[][] temp;
    static int t=0;
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st=new StringTokenizer(br.readLine());
        int n=Integer.valueOf(st.nextToken());
        int m=Integer.valueOf(st.nextToken());

        temp=new String[n+1][m+1];
        for(int i=1; i<=n; i++){
            String a=br.readLine();
            for(int j=1; j<=m; j++){
                temp[i][j]=String.valueOf(a.charAt(j-1));
            }
        }
        int min=Integer.MAX_VALUE;
        for(int i=1; i<=n-7; i++){
            for(int j=1; j<=m-7; j++){
                for(int k=0; k<=7; k++){
                    if((i+k)%2==1){
                        check(i+k,j,"B","W");
                    }
                    else {
                        check(i + k, j ,"W", "B");
                    }
                }
                min=Math.min(min,t);
                t=0;
                for(int k=0; k<=7; k++){
                    if((i+k)%2==1){
                        check(i+k,j,"W","B");
                    }
                    else{
                        check(i+k,j,"B","W");
                    }

                }
                min=Math.min(min,t);
                t=0;
            }
        }
        bw.write(min+"");
        bw.flush();

    }
    public static void check(int y, int x, String f, String s){
        for(int i=x; i<=x+7; i++){
            if((i-x)%2==0 && temp[y][i].equals(f)){
                t++;
            }
            else if((i-x)%2==1 && temp[y][i].equals(s)){
                t++;
            }
        }
    }

}