Envío 1504

Código

import java.util.Scanner;

public class Main {

    public boolean isMagic(int n, int[][] matrix) {
        int want = 0;
        for ( int r = 0; r < n; r++ ) {
            want += matrix[0][r];
        }

        // ROW
        for ( int r = 0; r < n; r++) {
            int sum = 0;
            for (int c = 0; c < n; c++) {
                sum += matrix[r][c];
            }
            if (sum != want) {
                return false;
            }
        }

        // COLUMN
        for (int c = 0; c < n; c++) {
            int sum = 0;
            for (int r = 0; r < n; r++) {
                sum += matrix[r][c];
            }
            if (sum != want) {
                return false;
            }
        }

        int sum = 0;
        for (int i = 0; i < n; i++) {
            sum += matrix[i][i];
        }
        if (sum != want) {
            return false;
        }

        sum = 0;
        for (int i = 0; i < n; i++) {
            sum += matrix[i][n-1-i];
        }
        if (sum != want) {
            return false;
        }
        return true;
    }

    public static void main(String[] args) {
        final int MAXN = 100;
        int[][] matrix = new int[MAXN][MAXN];

        Scanner in = new Scanner(System.in);
        int n = in.nextInt();

        for ( int r = 0; r < n; r++) {
            for ( int c = 0; c < n; c++) {
                matrix[r][c] = in.nextInt();
            }
        }

        Main solve = new Main();
        boolean isMagic = solve.isMagic(n, matrix);

        if (isMagic == true) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}