2nd task from 1.11

Main.java

package com.company;
import java.util.Scanner;

public class Main {
    static Scanner in = new Scanner(System.in);
    public static void main(String[] args) {
        int n = in.nextInt();
        int[][] a = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = in.nextInt();
            }
        }
        int k = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (a[i][j] == a[j][i]) {
                    k++;
                }
            }
        }
        System.out.println((k == n*n) ? "yes" : "no");
    }

}