using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        int[] arr = {11,12,15};

        int[] arr2 = {11,12,15};

        var list = new List<int[]>();

        list.Add(arr);

        list.Add(arr2);

        // List with 2 int arrays of the same values (11,12,15)

        // try grouped?     

        var grouped = list.GroupBy(x=>x);

        // try distinct?

        var distinct = list.Distinct();

        var d2 = list.SelectMany(x=>x).Distinct();

        // still gives me 2, should be 1 unique value           

        Console.WriteLine(grouped.Count());

        Console.WriteLine(distinct.Count());

        Console.WriteLine(d2.Count());

        // This way works

        var newList = new List<int[]>();

        foreach (var result in list) 

        {

            var found = newList.Where(x=>Enumerable.SequenceEqual(x, result));

            if (!found.Any()) {

                newList.Add(result);

            }

        }

        Console.WriteLine(newList.Count());

    }

}