using System; using System.Linq; using System.Collections.Generic;  

public class Program

{

    public static void Main()

    {

        var ValidationIdToInsert = new List<Int16>();  var ValidationIdToDelete = new List<Int16>(); var ValidationIdToUpdateWith = new List<Int16>();   

        var ValidationIdUpdateNew = new List<Int16>(); var intersect = new List<Int16>(); var temp = new List<Int16>();     

        //List<Int16> Current = new List<Int16> { 6,15,20,22,24}; 

        //List<Int16> New = new List<Int16> {6,15,20};  //Cnd- 1

        List<Int16> Current = new List<Int16>{6,12,13,14,15}; 

        List<Int16> New = new List<Int16>{6,12,13,14,15};

        intersect = Current.Intersect(New).ToList();

        string Newstr = string.Empty; string Currentstr = string.Empty;     

        if(Current != null && New != null && Current.Count > New.Count)

        {   //No Insert. At least one Delete

             Console.WriteLine("Condition - 1");

            if(intersect != null && intersect.Count > 0 && New.Count > intersect.Count)

            {

                Console.WriteLine("Condition - 1.1");

                Current  = Current.Except(intersect).ToList(); //20 22 24

                New = New.Except(intersect).ToList();   // 12 13

                temp.AddRange(Current); //20 22 24

                temp.RemoveRange(0, New.Count); // 24

                ValidationIdToUpdateWith = Current.Except(temp).ToList();

                ValidationIdUpdateNew.AddRange(New);

                ValidationIdToDelete.AddRange(temp);

            }

            else if(intersect != null && intersect.Count > 0 && New.Count <= intersect.Count)

            {                   

                Console.WriteLine("Condition- 1.2");

                Current  = Current.Except(intersect).ToList(); //20 22 24

                ValidationIdToDelete.AddRange(Current);                     

            }

            else if(intersect != null && intersect.Count <= 0)

            { 

                Console.WriteLine("Condition- 1.3");

                temp.AddRange(Current);

                temp.RemoveRange(0, New.Count);

                ValidationIdToUpdateWith = Current.Except(temp).ToList();

                ValidationIdUpdateNew.AddRange(New);

                ValidationIdToDelete.AddRange(temp);

            }

        }//Current.Count > New.Count

        else if (Current.Count < New.Count) 

        { //At Least one insert, No Delete

            Console.WriteLine("Condition- 2");

            if(Current != null && Current.Count <= 0)

            {

                Console.WriteLine("Condition- 2.1");

                ValidationIdToInsert.AddRange(New);

            }

            else if(intersect != null && intersect.Count > 0 && New.Count > intersect.Count)

            {

                Console.WriteLine("Condition- 2.2");

                Current  = Current.Except(intersect).ToList(); //21

                New = New.Except(intersect).ToList();   //20 22 24

                temp.AddRange(New); //20 22 24

                temp.RemoveRange(0, Current.Count); // 22 24

                ValidationIdUpdateNew = New.Except(temp).ToList();

                ValidationIdToUpdateWith.AddRange(Current);

                ValidationIdToInsert.AddRange(temp);

            }

            else if(intersect != null && intersect.Count > 0 && New.Count <= intersect.Count)

            {

                Console.WriteLine("Condition- 2.3");

                Current  = Current.Except(intersect).ToList(); //20 22 24

                ValidationIdToDelete.AddRange(Current);     

            }

        }

        else if (intersect != null && Current.Count == New.Count) 

        {

            Console.WriteLine("Condition- 3");

            if(intersect.Count > 0)

            {

                Current  = Current.Except(intersect).ToList();

                New = New.Except(intersect).ToList();               

            }   

            ValidationIdToUpdateWith.AddRange(Current);

            ValidationIdUpdateNew.AddRange(New);            

        }

        else if (New.Count == intersect.Count) 

        {

            Console.WriteLine("Nothing to do - Condition- 4");

        }

        else if(Current != null && Current.Count == 0)

        {

            ValidationIdToInsert.AddRange(Current); 

        }

        string Insert = string.Empty; string Delete = string.Empty; string Update = string.Empty; string UpdateWith = string.Empty; string CommonInBoth = string.Empty; 

        string NewNotInCurrentstr = string.Empty;   string CurrentNotInNewstr = string.Empty;        

         foreach(var item in Current)

          {      

             Currentstr += item + ",";          

          }

         Console.WriteLine("Current List: " + Currentstr);

             foreach(var item in New)

          {      

             Newstr += item + ",";          

          }

         Console.WriteLine("New List: " + Newstr + "\n");       

​

         foreach(var item in intersect)

          {      

             CommonInBoth += item + ",";            

          }

         Console.WriteLine("CommonInBoth List: " + CommonInBoth);

        foreach(var item in ValidationIdToInsert)

          {      

             Insert += item + ",";          

          }

         Console.WriteLine("Insert List: " + Insert);

        foreach(var item in ValidationIdToDelete)

          {      

             Delete += item + ",";          

          }

         Console.WriteLine("Delete List: " + Delete);

        foreach(var item in ValidationIdToUpdateWith)

          {      

             Update += item + ",";          

          }

         Console.WriteLine("UpdateWith List: " + Update);

        foreach(var item in ValidationIdUpdateNew)

          {      

             UpdateWith += item + ",";          

          }

         Console.WriteLine("UpdateNew List: " + UpdateWith);    

    }//Main()

}