250118 게리맨더링 2

public static void main(String[] args) throws Exception {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int n = Integer.parseInt(br.readLine().trim());
	int[][] array = new int[n + 1][n + 1];
	int[][] prefixSum = new int[n + 1][n + 1];
	int totalSum = 0;

	for (int i = 1; i <= n; i++) {
		StringTokenizer st = new StringTokenizer(br.readLine().trim());
		for (int j = 1; j <= n; j++) {
			totalSum += array[i][j] = Integer.parseInt(st.nextToken());
			prefixSum[i][j] = prefixSum[i - 1][j] + prefixSum[i][j - 1] - prefixSum[i - 1][j - 1] + array[i][j];
		}
	}

	int currentSum, maxSum, minSum, sectionSum, result = Integer.MAX_VALUE;

	for (int i = 1; i <= n - 2; i++) {
		for (int j = 2; j <= n - 1; j++) {
			for (int k = 1; j - k > 0; k++) {
				for (int l = 1; j + l <= n && i + k + l <= n; l++) {
					currentSum = 0;
					sectionSum = 0;

					if (i > 1) {
						currentSum += prefixSum[i - 1][j];
					}
					for (int m = i, p = j - 1; m < i + k; m++, p--) {
						currentSum += prefixSum[m][p] - prefixSum[m - 1][p] - prefixSum[m][0] + prefixSum[m - 1][0];
					}
					maxSum = currentSum;
					minSum = currentSum;
					sectionSum += currentSum;

					currentSum = 0;
					if (j + l < n) {
						currentSum += prefixSum[i + l][n] - prefixSum[0][n] - prefixSum[i + l][j + l] + prefixSum[0][j + l];
					}
					for (int m = j + l, p = i + l - 1; m > j; m--, p--) {
						currentSum += prefixSum[p][m] - prefixSum[0][m] - prefixSum[p][m - 1] + prefixSum[0][m - 1];
					}
					maxSum = Math.max(maxSum, currentSum);
					minSum = Math.min(minSum, currentSum);
					sectionSum += currentSum;

					currentSum = 0;
					if (i + k + l < n) {
						currentSum += prefixSum[n][n] - prefixSum[i + k + l][n] - prefixSum[n][j + l - k - 1] + prefixSum[i + k + l][j + l - k - 1];
					}
					for (int m = i + k + l, p = j + l - k + 1; m > i + l; m--, p++) {
						currentSum += prefixSum[m][n] - prefixSum[m - 1][n] - prefixSum[m][p - 1] + prefixSum[m - 1][p - 1];
					}
					maxSum = Math.max(maxSum, currentSum);
					minSum = Math.min(minSum, currentSum);
					sectionSum += currentSum;

					currentSum = 0;
					if (j - k > 0) {
						currentSum += prefixSum[n][j - k - 1] - prefixSum[i + k - 1][j - k - 1] - prefixSum[n][0] + prefixSum[i + k - 1][0];
					}
					for (int m = j - k, p = i + k + 1; m < j + l - k; m++, p++) {
						currentSum += prefixSum[n][m] - prefixSum[p - 1][m] - prefixSum[n][m - 1] + prefixSum[p - 1][m - 1];
					}
					maxSum = Math.max(maxSum, currentSum);
					minSum = Math.min(minSum, currentSum);
					sectionSum += currentSum;

					currentSum = totalSum - sectionSum;
					maxSum = Math.max(maxSum, currentSum);
					minSum = Math.min(minSum, currentSum);
					result = Math.min(result, maxSum - minSum);
				}
			}
		}
	}

	System.out.println(result);
}

출처:https://www.acmicpc.net/problem/17779