180210_1018_체스판 다시 칠하기

	//https://www.acmicpc.net/problem/1018 #include <iostream>
	#include <algorithm>
	using namespace std;
	int N, M, mn;
	char map[50][50];
	void input(){
	cin >> N >> M;
	for(int i=0; i<N; i++)
	cin >> map[i];
	}
	int painting_white_fst(int y, int x){
	int cnt=0;
	for(int i=y; i<y+8; i++){
	for(int j=x; j<x+8; j++){
	if((y%2)==(i%2)){
	if((x%2)==(j%2)){ if(map[i][j]=='B') cnt++;}
	else { if(map[i][j]=='W') cnt++;}
	}
	else {
	if((x%2)==(j%2)){ if(map[i][j]=='W') cnt++;}
	else { if(map[i][j]=='B') cnt++;}
	}
	}
	}
	return cnt;
	}
	int painting_black_fst(int y, int x){
	int cnt=0;
	for(int i=y; i<y+8; i++){
	for(int j=x; j<x+8; j++){
	if((y%2)==(i%2)){
	if((x%2)==(j%2)){ if(map[i][j]=='W') cnt++;}
	else { if(map[i][j]=='B') cnt++;}
	}
	else {
	if((x%2)==(j%2)){ if(map[i][j]=='B') cnt++;}
	else { if(map[i][j]=='W') cnt++;}
	}
	}
	}
	return cnt;
	}
	int find(){
	int ans=66;
	for(int i=0; i<=N-8; i++){
	for(int j=0; j<=M-8; j++){
	mn=min(painting_white_fst(i,j),painting_black_fst(i,j));
	ans=min(ans,mn);
	}
	}
	return ans;
	}
	int main(){
	input();
	cout << find();
	}

-> 수정

	//https://www.acmicpc.net/problem/1018 #include <iostream>
	#include <algorithm>
	using namespace std;
	int N, M, mn;
	char map[50][50];
	void input(){
	cin >> N >> M;
	for(int i=0; i<N; i++)
	cin >> map[i];
	}
	int painting_white_fst(int y, int x){
	int cnt=0;
	for(int i=y; i<y+8; i++){
	for(int j=x; j<x+8; j++){
	if((y%2)==(i%2)){
	if((x%2)==(j%2)){ if(map[i][j]=='B') cnt++;}
	else { if(map[i][j]=='W') cnt++;}
	}
	else {
	if((x%2)==(j%2)){ if(map[i][j]=='W') cnt++;}
	else { if(map[i][j]=='B') cnt++;}
	}
	}
	}
	return cnt;
	}
	int find(){
	int ans=66;
	for(int i=0; i<=N-8; i++){
	for(int j=0; j<=M-8; j++){
	int tmp=painting_white_fst(i,j);
	mn=min(tmp,64-tmp);
	ans=min(ans,mn);
	}
	}
	return ans;
	}
	int main(){
	input();
	cout << find();
	}