O3. Diagonal Difference / Multidimensional Arrays - Exercises

import java.util.*;

public class DiagonalDifference {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int size = Integer.parseInt(scan.nextLine());
        int[][] matrix = readMatrix(scan, size);
        int sum = 0;
        for (int row = 0; row < size; row++) {
            sum += matrix[row][row];
        }
        for (int row = 0; row < size; row++) {
            sum -= matrix[size - 1-row][row];
        }
        System.out.println(Math.abs(sum));
    }

    private static int[][] readMatrix(Scanner scan, int size) {
        int[][] matrix = new int[size][size];
        for (int i = 0; i < size; i++) {
            matrix[i] = Arrays.stream(scan.nextLine().split("\\s+")).mapToInt(Integer::parseInt).toArray();
        }
        return matrix;
    }
}