aush

#IfWinActive, WoW
{
  !F4::Send !4
}

using System;
using System.Linq;

class Program
{
    static void Main()
    {
        Console.WriteLine(GetLastStanding(11, 4));
    }

    static int GetLastStanding(int n, int step)
    {
        var items = Enumerable.Range(0, n)
                        .Select(position => new Item { Position = position }).ToArray();
        var i = 0;
        var stepCounter = 0;
        var nCounter = n;
        while (nCounter > 1)
        {
            if (!items[i].Marked && ++stepCounter == step)
            {
                stepCounter = 0;
                items[i].Marked = true;
                --nCounter;
                Console.WriteLine(string.Join(", ",
                    items.Select(item => item.Marked ?
                        "_" : (item.Position + 1).ToString())));
            }

            i = (i + 1) % n;
        }
        return items.Single(item => !item.Marked).Position;
    }

    struct Item
    {
        public int Position;
        public bool Marked;
    }
}

internal class Program
{
    private static void Main(string[] args)
    {
        foreach (var combination in GenerateCombinations(3, 5, 1))
        {
            foreach (var i in combination)
            {
                Console.Write(i + ", ");
            }
            Console.WriteLine();
        }
        Console.WriteLine("----------------");

        foreach (var combination in GenerateUniqueCombinations(3, 5, 1))
        {
            foreach (var i in combination)
            {
                Console.Write(i + ", ");
            }
            Console.WriteLine();
        }

        Console.ReadLine();
    }

    private static List<List<int>> GenerateUniqueCombinations(int stacksCount, int totalAmount, int step)
    {
        var generatedCombinations = GenerateCombinations(stacksCount, totalAmount, step);

        var dicts = new List<Dictionary<int, int>>();
        foreach (var combination in generatedCombinations)
        {
            var dict = new Dictionary<int, int>();
            foreach (var i in combination)
            {
                if (dict.ContainsKey(i))
                {
                    dict[i]++;
                }
                else
                {
                    dict[i] = 1;
                }
            }
            if (!dicts.Any(d => DictionaryEquals(d, dict)))
            {
                dicts.Add(dict);
            }
        }

        return dicts.Select(d =>
        {
            var r = new List<int>();
            foreach (var key in d.Keys)
            {
                if (d[key] == 1)
                {
                    r.Add(key);
                }
                else
                {
                    r.AddRange(Enumerable.Repeat(key, d[key]));
                }
            }
            return r;
        }).ToList();
    }

    private static bool DictionaryEquals(Dictionary<int, int> x, Dictionary<int, int> y)
    {
        foreach (var key in x.Keys)
        {
            if (!y.ContainsKey(key))
            {
                return false;
            }

            if (x[key] != y[key])
            {
                return false;
            }
        }

        foreach (var key in y.Keys)
        {
            if (!x.ContainsKey(key))
            {
                return false;
            }

            if (x[key] != y[key])
            {
                return false;
            }
        }

        return true;
    }

    private static List<List<int>> GenerateCombinations(int stacksCount, int totalAmount, int step)
    {
        var result = new List<List<int>>();

        if (stacksCount > 1)
        {

            for (var i = 1; i < totalAmount / step; ++i)
            {
                var add = i * step;

                foreach (var generated in GenerateCombinations(stacksCount - 1, totalAmount - add, step))
                {
                    generated.Insert(0, add);
                    result.Add(generated);
                }
            }
        }
        else
        {
            result.Add(new List<int> { totalAmount });
        }

        return result;
    }
}

the C# compiler was not designed to be a component of a security system, so don't use it as one