using System;

using System.Collections.Generic;

using System.Linq;

​

class Program

{

    /*

    Please print the menu tree on Console. 

    Each nested level should be shifted on 4 stars '*' from the parent. 

    The order of same level items should be the same as the order in the original list.

    <c>-1</c> indicates the root level. At lease one root level will always present.

​

    Please see the sample output:

    Printed menu:

    Menu1

    Menu2

    ****Menu4

    ********Menu5

    Menu3

    ****Menu8

    ********Menu6

    ********Menu7

    */

​

    private static readonly IList<Menu> MenuItems = new List<Menu>

    {

        new Menu(1, -1, "Menu1"),

        new Menu(2, -1, "Menu2"),

        new Menu(3, -1, "Menu3"),

        new Menu(4, 2, "Menu4"),

        new Menu(5, 4, "Menu5"),

        new Menu(6, 8, "Menu6"),

        new Menu(7, 8, "Menu7"),

        new Menu(8, 3, "Menu8"),

    };

​

    class Menu

    {

        public Menu(int id, int parentId, string name)

        {

            Id = id;

            ParentId = parentId;

            Name = name;

        }

​

        public int Id { get; }

        public int ParentId { get; }

        public string Name { get; }

    }

​

    public static void Main()

    {

        Console.WriteLine("Printed menu:");

        PrintMenu(MenuItems);

    }

​

    private static void PrintMenu(IEnumerable<Menu> menuItems)

    {

​

        var rootLevel = menuItems.Where(x => x.ParentId == -1).ToList();

        foreach (var root in rootLevel)

        {

            PrintMenuItem(root, 0);

        }

    }

    //Print menu item with indentation

    private static void PrintMenuItem(Menu menuItem, int indentation)

    {

        Console.WriteLine(new string('*', indentation) + menuItem.Name);

        var children = MenuItems.Where(x => x.ParentId == menuItem.Id).ToList();

        foreach (var child in children)

        {

            PrintMenuItem(child, indentation + 4);

        }

    }

}