230905 고고학 최고의 발견(refactor)

public int solution(int[][] clockHands) {
	int n = clockHands.length;
	int answer = Integer.MAX_VALUE;

	for (int i = 0; i < Math.pow(4, n); i++) {
		int[][] copyArr = copy2DArray(clockHands);
		int count = 0;
		int a = i;

		for (int j = 0; j < n; j++) {
			int cnt = a % 4;
			a /= 4;
			rotateClockHands(copyArr, 0, j, cnt);
			count += cnt;
		}

		for (int row = 1; row < n; row++) {
			for (int col = 0; col < n; col++) {
				int cnt = (4 - copyArr[row - 1][col]) % 4;
				rotateClockHands(copyArr, row, col, cnt);
				count += cnt;
			}
		}

		if (Arrays.equals(copyArr[n - 1], new int[n])) {
			return count;
		}
	}
	return answer;
}

private static int[][] copy2DArray(int[][] original) {
	int n = original.length;
	int[][] copy = new int[n][n];
	for (int i = 0; i < n; i++) {
		System.arraycopy(original[i], 0, copy[i], 0, n);
	}
	return copy;
}

private static void rotateClockHands(int[][] clockHands, int row, int col, int cnt) {
	int n = clockHands.length;
	clockHands[row][col] = (clockHands[row][col] + cnt) % 4;
	if (row > 0)
		clockHands[row - 1][col] = (clockHands[row - 1][col] + cnt) % 4;
	if (col > 0)
		clockHands[row][col - 1] = (clockHands[row][col - 1] + cnt) % 4;
	if (row < n - 1)
		clockHands[row + 1][col] = (clockHands[row + 1][col] + cnt) % 4;
	if (col < n - 1)
		clockHands[row][col + 1] = (clockHands[row][col + 1] + cnt) % 4;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/131702