using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        List<int> a = new List<int>() { 1, 2, 2, 3, 3, 4, 4, 5 };

        var b = Distinct(a.ToArray());

        foreach(int i in b)

        {

            // should return 1,2,3,4,5

            Console.WriteLine(i);

        }

    }

​

    static int[] Distinct(int[] intArray)

    {

    }

}