using System;

using System.Collections.Generic;

  /// input words: ["yo", "act","flop", "tac", "foo","cat","oy","olfp"]

  /// output:[["yo","oy"],["flop","olfp"],["act","tac","cat"],["foo"]]

public class Program

{

    public static void Main()

    {

          var words = new List<string> { "yo", "act", "flop", "tac", "foo", "cat", "oy", "olfp" };

    }

    private static List<List<string>> DoGroupAnagrams(List<string> words)

    {

        var output = new List<List<string>>();

        var resultMap = new Dictionary<string, List<string>>();

        if(words.Count <=1)

        {

            output.Add(words);

            return output;

        }

        foreach(var item in words)

        {

            var charValue = item.ToCharArray();

            Array.Sort(charValue);

            var sortedString = new string(charValue);

            if(!resultMap.ContainsKey(sortedString))

            {

                var lst = new List<string>();

                lst.Add(item);

                resultMap.Add(sortedString, lst);

            }

            else

                resultMap[sortedString].Add(item);      

        }

        if(resultMap.Count > 0)

        {

            foreach(var item in resultMap)

            {

                var itm = new List<string>();

                if(item.Value.Count > 0)

                    foreach(var i in item.Value)

                        itm.Add(i);

                output.Add(itm);

            }

        }

        return output;

    }

}