Snake

package com.company;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int c;
        do{
            System.out.println("1. Горизонтальная 2. Вертикальная 3. По спирали 0. Выход");
            System.out.print("Ваш выбор ");
            c=sc.nextInt();
            if (c!=0){
                System.out.println("Задайте размер массива N ");
                int n=sc.nextInt();
                switch (c){
                    case 1: print(horizontal(n)); break;
                    case 2: print(vertical(n)); break;
                    case 3: print(spiral(n)); break;
                }
            }
        } while (c!=0);
    }
    static int [][] horizontal(int n){
        int a[][]=new int [n][n];
        int i=0, j=0, dj=1;
        for (int k=1; k<=n*n; k++){
            a[i][j]=k;
            j=j+dj;
            if (j==n || j==-1) {
                dj*=-1;
                i++;
                j+=dj;
            }
        }
        return a;
    }
    static int [][] vertical(int n){
        int a[][]=new int [n][n];
        int i=0, j=0, dj=1;
        for (int k=1; k<=n*n; k++){
            a[j][i]=k;
            j=j+dj;
            if (j==n || j==-1) {
                dj*=-1;
                i++;
                j+=dj;
            }
        }
        return a;
    }
    static void print(int b[][]){
        for (int i=0; i<b.length; i++){
            for (int j=0; j<b[i].length; j++)
                System.out.print(b[i][j]+"\t");
            System.out.println();
        }
    }
    static int [][] spiral(int n){
        int a[][]=new int [n][n];
        int i=0, j=n-1;
        int value = n*n;
        while (n != 0){
            int k = 0;
            do {a[i][j--] = value--;} while (++k < n-1);
            for (k = 0; k <n-1;k++) a[i++][j] = value--;
            for (k = 0; k <n-1;k++) a[i][j++] = value--;
            for (k = 0; k <n-1;k++) a[i--][j] = value--;
            ++i; --j; n = n < 2 ? 0: n-2;
        }
        return a;
    }
}