using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("NORMAL RUN STARTING:");

        List<int> start = new List<int>{ 1, 2, 3, 4 };

        List<List<int>> allSubset =GetCombination<int>(start, 2);

        List<int> sumOfAllSubset = SubsetSum(allSubset);

        sumOfAllSubset = ClearList(sumOfAllSubset);

        //sumOfAllSubset.ForEach(s=> Console.WriteLine(s));

        Console.WriteLine(" {0}  =>  {1} ", string.Join(", ", start), string.Join(", ", sumOfAllSubset));

        Console.WriteLine("Exiting...");

    }

    static List<int> ClearList( List<int> DoublonList ) {

        DoublonList.Sort();

        Int32 index = 0;

        while (index < DoublonList.Count - 1)

        {

            if (DoublonList[index] == DoublonList[index + 1])

                DoublonList.RemoveAt(index);

            else

                index++;

        }

        return DoublonList;

        // return DoublonList.Distinct().ToList(); 

    }

    static List<int> SubsetSum(List<List<int>> Subsets) {

        List<int> result = new List<int>();

        Subsets.ForEach( s => result.Add(s.Sum()) );

        return result;

    }

    public static List<List<T>> GetCombination<T>(List<T> inputList, int minimumItems = 1)  {

        int count = (int)Math.Pow(2, inputList.Count) - 1;

        List<List<T>> result = new List<List<T>>(count + 1);

        if (minimumItems == 0)

            result.Add(new List<T>());

        for (int i = 1; i <= count; i++)

        {

            List<T> combinason = new List<T>(inputList.Count);

            for (int j = 0; j < inputList.Count; j++)

            {

                if ((i >> j & 1) == 1)

                    combinason.Add(inputList[j]);

            }

            if (combinason.Count >= minimumItems)

                result.Add(combinason);

        }

        return result;

    }

}