using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

         var result = Permutations<string>(new List<string>() { "A", "B","C" });

            foreach (var item in result)

            {               

                Console.WriteLine("[" + string.Join(",", item.Select(x => x.ToString())) + "]");

            }

    }

    public static List<List<T>> Permutations<T>(List<T> list)

        {

            var result = new List<List<T>>();

            if (list.Count == 1)

            { 

                result.Add(list);

                return result;

            }

            foreach (var element in list)

            { 

                var remainingList = new List<T>(list);

                remainingList.Remove(element); 

                foreach (var item in Permutations<T>(remainingList))

                { 

                    item.Add(element);

                    result.Add(item);

                }

            }

            return result;

        }

}