백준 1018

www.acmicpc.net/problem/1018

1. 필터 생성

1) char b_first[8][8]

BWBWBWBW

WBWBWBWB

BWBWBWBW

WBWBWBWB

BWBWBWBW

WBWBWBWB

BWBWBWBW

WBWBWBWB

 

2) char w_first[8][8]

WBWBWBWB

BWBWBWBW

WBWBWBWB

BWBWBWBW

WBWBWBWB

BWBWBWBW

WBWBWBWB

BWBWBWBW

 

2. 시작 좌표 바꿔가면서 필터[][]와 input[][] 값이 다르면 count++

3. 최솟값 찾기

#include <iostream>
#define rep(i, n) for(int i = 0; i<n; i++)
using namespace std;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
 
    char b_first[8][8];
    char w_first[8][8];
 
    // 필터 초기화
    rep(i, 8) {
        rep(j, 8) {
            if ((i + j) % 2 == 0) {
                b_first[i][j] = 'B';
                w_first[i][j] = 'W';
            }
            else {
                b_first[i][j] = 'W';
                w_first[i][j] = 'B';
            }
        }
    }
 
    char input[50][50];
    int n, m;
    cin >> n >> m;
    rep(i, n) {
        rep(j, m)
            cin >> input[i][j];
    }
    
    int min = 987654321;
    // 시작 위치 바꿔가면서 필터와 input 비교
    for (int i = 0; i <= n - 8; i++) {
        for (int j = 0; j <= m - 8; j++) {
            int b_cnt = 0;
            int w_cnt = 0;
 
            for(int k = i; k<i+8; k++){
                for (int l = j; l < j + 8; l++) {
                    if (b_first[k - i][l - j] != input[k][l])
                        b_cnt++;
                    if (w_first[k - i][l - j] != input[k][l])
                        w_cnt++;
                }
            }
            // 최솟값 찾기
            int temp = b_cnt < w_cnt ? b_cnt : w_cnt;
            min = min < temp ? min : temp;
        }
    }
    cout << min;
}