CodeProject Code Challenge : Largest Group Sum, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            foreach (var test in new List<List<int>>()
            {
                new List<int>(),
                new List<int>() { -1, -2, -5, -4, -5, -1, -2, -11 },
                new List<int>() { 1, 2, 5, 4, 5, 1, 2, 11 },
                new List<int>() { 1, 2, -5, 4, 5, -1, 2, -11 },
                new List<int>() { 5, -5, 5, -10, 5, -5, 5 },
                new List<int>() { 5, -5, 5, -5, 5 }
            })
            {
                var lg = test.LargestGroupSumList();
                Console.WriteLine("For [{0}], the largest group is [{1}] with a sum of {2}", string.Join(",", test), string.Join(",", lg), lg.Sum());
            }
            Console.WriteLine("\r\n-- Press any key to exit --");
        }
    }

public static class HelperExtensions
    {
        public static IList<int> LargestGroupSumList(this IList<int> list)
        {
            if (!list.Any() || !list.Any(x => x > 1))
                return new List<int>();
            else if (!list.Any(x => x < 1))
                return list;
            else
            {
                var groups = new List<List<int>>();
                for (int i = 0; i < list.Count; i++)
                    for (int j = 0; j < list.Count - i; j++)
                        groups.Add(list.Skip(i).Take(j + 1).ToList());
                return groups.OrderByDescending(X => X.Count).OrderByDescending(x => x.Sum()).First();
            }
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,16 sec, absolute running time: 0,09 sec, cpu time: 0,09 sec, average memory usage: 13 Mb, average nr of threads: 3