using System;

using System.Collections.Generic;

using System.Linq;

using System.Diagnostics; 

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Get difference between two unordered, not unique (duplicates) lists!");

            Console.WriteLine("Solution by https://metadataconsulting.blogspot.com/2021/02/CSharp-dotNet-Get-difference-between-two-unordered-not-unique-lists-aka-duplicates-allowed-within-a-list-and-across-both-lists.html");

            Console.WriteLine();

            Stopwatch sw = new Stopwatch();

            sw.Start(); 

​

            //UNORDERED, NOT UNIQUE lists, lists with duplicates 

            string[] arrA = new string[] { "1", "1", "2", "3", "4", "5", "9", "7", "7", "7" };

            string[] arrB = new string[] { "1", "1", "2", "2", "3", "4", "5", "5", "5", "5" };

​

            //DESIRED RESULT = 2,5,5,5,7,7,7,9 OR 2,5,5,5,9,7,7,7 OR 9,7,7,7,2,5,5,5 UNORDERED IS SUFFICIENT, WE LOOKING FOR SPEED

            IEnumerable<string> Uniondifference = arrA.Union(arrB);

            sw.Stop();  

            Console.WriteLine("RemoveRage Result = " + string.Join(",", Uniondifference) + " in " + sw.ElapsedTicks + " ticks.");

            sw.Reset();

            sw.Start();

            IEnumerable<string> AllArr = arrA.Concat(arrB);

             //Find Dups

             var arrDups = AllArr.GroupBy(x=>x)

              .Where(g=>g.Count()>1)

              .Select(y=>y.Key)

              .ToList();

            Console.WriteLine("RemoveRage Result = " + string.Join(",", arrDups) + " in " + sw.ElapsedTicks + " ticks.");

            var arrDupsCnt = AllArr.GroupBy(x=>x)

              .Where(g=>g.Count()>1)

              .Select(y=> new { Element = y.Key, Counter = y.Count()})

              .ToList();

            Console.WriteLine("RemoveRage Result = " + string.Join(",", arrDupsCnt) + " in " + sw.ElapsedTicks + " ticks.");

            sw.Stop();  

    }

}