using System;

using System.Text;

using System.Linq;

using System.Collections.Generic;

public class Program

{

public static List<E> ShuffleList<E>(List<E> inputList)

{

    var r = new Random();

​

    for (int i = 0; i < inputList.Count - 1; i++)

    {

        var randomIndex = r.Next(i, inputList.Count); 

        var temp = inputList[i];

        inputList[i] = inputList[randomIndex];

        inputList[randomIndex] = temp;

    }

    return inputList;

}

    public static void Main()

    {

        var arr = ShuffleList(Enumerable.Range(0, 20).ToList());

        foreach(var e in arr)

            Console.Write(e + "  ");

    }

}