P3392 涂国旗（DFS思想+for循环）

import java.util.Scanner;

public class P3392 {
	static int N,M,count;
	static int wCount=0,bCount=0,rCount=0;
	static char[][] grid = new char[50][50];
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();
		count=N*M;
		for(int i=0;i<N;i++) {
			grid[i] = sc.next().toCharArray();
		}
		dfs();
		System.out.println(count);
	}
	
	private static void dfs() {
		for(int h1=0;h1<N-2;h1++) {
			for(int i=0;i<M;i++) {
				if('W'!=grid[h1][i]) {
					wCount++;
				}
			}
			bCount = 0;
			for(int h2=h1+1;h2<N-1;h2++) {
				for(int i=0;i<M;i++) {
					if('B'!=grid[h2][i]) {
						bCount++;
					}
				}
				rCount = 0;
				for(int h3=h2+1;h3<N;h3++) {
					for(int i=0;i<M;i++) {
						if('R'!=grid[h3][i]) {
							rCount++;
						}
					}
				}
				int num = wCount+bCount+rCount;
				count = count>num?num:count;
			}
		}
		
	}
}