gistfile1.txt

import java.util.*;

public class Taikaneliotehdas {

    private int x;
    private int y;
    private Taikanelio nelio;

    public Taikanelio luoTaikanelio(int koko) {

        Taikanelio nelio = new Taikanelio(koko);
        this.nelio = nelio;
        // Create a random number generator
        Random random = new Random();

        this.x = 0;
        this.y = 0;

        if (koko % 2 == 1) {

            for (int i = 0; i < nelio.getLeveys() * nelio.getKorkeus(); i++) {

                int randomNumber = random.nextInt(100 - 1) + 1;
                System.out.println(randomNumber);
                // nelio.asetaArvo(0, 0, 1);
                // nelio.asetaArvo(2, 2, 2);
                System.out.println("i" + i);
                if (i == 0) {
                        System.out.println("sdsd");
                    x = nelio.getLeveys() / 2;
                    y = i;
                    nelio.asetaArvo(x, y, 123);
                    System.out.println(nelio.toString());
                }

                if (i > 1) {
                    x++;
                    y++;

                    if (nelio.annaArvo(x, y) == 0) {
                        nelio.asetaArvo(x, y, randomNumber);
                        // break;
                    }

                    if (nelio.annaArvo(x, y) == -1 && x > y) {
                        x = 0;
                        nelio.asetaArvo(x, y, randomNumber);
                        //break;
                    }

                    if (nelio.annaArvo(x, y) == -1 && y > x) {
                        y = 0;
                        nelio.asetaArvo(x, y, randomNumber);
                        //break;

                    }
                }
            }
        }

        return nelio;
    }

    public boolean isTheSquareSlotReserved() {

        if (nelio.annaArvo(x, y) > 0 && y <= nelio.getKorkeus() && x <= nelio.getLeveys()) {
            return true;
        }
        return false;
    }
}

******************************************************************************************************************************************************************************************************************************************************
Main



public class Main {

    public static void main(String[] args) {
        // Testaa Taikanelio-luokkaasi täällä
     
       
        
        Taikaneliotehdas tt = new Taikaneliotehdas();
        System.out.println(tt.luoTaikanelio(3));
        
    }
}

*********************************************************************************************************************************************************************************************************
Luokka Taikanelio.java


import java.util.ArrayList;
import java.util.Collections;
import java.util.*;

public class Taikanelio {

    private int[][] nelio;

    // valmis konstruktori
    public Taikanelio(int koko) {
        if (koko < 2) {
            koko = 2;
        }

        this.nelio = new int[koko][koko];
    }

    // toteuta nämä kolme metodia
    public ArrayList<Integer> rivienSummat() {

        ArrayList<Integer> sumArray = new ArrayList<>();

        int sum = 0;

        for (int row = 0; row < this.nelio.length; row++) {

            for (int col = 0; col < this.nelio.length; col++) {
                sum += this.nelio[row][col];

            }
            sumArray.add(sum);
            sum = 0;
        }

        return sumArray;
    }

    public ArrayList<Integer> sarakkeidenSummat() {
        ArrayList<Integer> sumArray = new ArrayList<>();

        int sum = 0;

        for (int row = 0; row < this.nelio.length; row++) {

            for (int col = 0; col < this.nelio.length; col++) {
                sum += this.nelio[col][row];

            }
            sumArray.add(sum);
            sum = 0;
        }

        return sumArray;
    }

    public ArrayList<Integer> lavistajienSummat() {
        ArrayList<Integer> sumArray = new ArrayList<>();

        int sumRight = 0;
        int sumLeft = 0;

        for (int row = 0; row < this.nelio.length; row++) {
            sumRight += this.nelio[row][row];
        }

        sumArray.add(sumRight);
        int counter = 0;
        for (int col = this.nelio.length - 1; col > -1; col--) {
            sumLeft += this.nelio[counter][col];
            counter++;
        }

        sumArray.add(sumLeft);
        return sumArray;
    }

    // valmiit apumetodit -- älä koske näihin
    public boolean onTaikanelio() {
        return summatSamat() && kaikkiNumerotEri();
    }

    public ArrayList<Integer> annaKaikkiNumerot() {
        ArrayList<Integer> numerot = new ArrayList<>();
        for (int y = 0; y < nelio.length; y++) {
            for (int x = 0; x < nelio[y].length; x++) {
                numerot.add(nelio[y][x]);
            }
        }

        return numerot;
    }

    public boolean kaikkiNumerotEri() {
        ArrayList<Integer> numerot = annaKaikkiNumerot();

        Collections.sort(numerot);
        for (int i = 1; i < numerot.size(); i++) {
            if (numerot.get(i - 1) == numerot.get(i)) {
                return false;
            }
        }

        return true;
    }

    public boolean summatSamat() {
        ArrayList<Integer> summat = new ArrayList<>();
        summat.addAll(rivienSummat());
        summat.addAll(sarakkeidenSummat());
        summat.addAll(lavistajienSummat());

        if (summat.size() < 3) {
            return false;
        }

        for (int i = 1; i < summat.size(); i++) {
            if (summat.get(i - 1) != summat.get(i)) {
                return false;
            }
        }

        return true;
    }

    public int annaArvo(int x, int y) {
        if (x < 0 || y < 0 || x >= getLeveys() || y >= getKorkeus()) {
            return - 1;
        }

        return this.nelio[y][x];
    }

    public void asetaArvo(int x, int y, int arvo) {
        if (x < 0 || y < 0 || x >= getLeveys() || y >= getKorkeus()) {
            return;
        }

        this.nelio[y][x] = arvo;
    }

    public int getLeveys() {
        return this.nelio.length;
    }

    public int getKorkeus() {
        return this.nelio.length;
    }

    @Override
    public String toString() {
        String palautus = "";
        for (int y = 0; y < nelio.length; y++) {
            for (int x = 0; x < nelio[y].length; x++) {
                palautus += nelio[y][x] + "\t";
            }

            palautus += "\n";
        }

        return palautus;
    }
}