demo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ITHS1._3
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> a = new List<int>() { 1,3,5};
            List<int> b = new List<int>() { 2, 4, 6, 8 };
            List<int> newList = Zip(a, b);
            newList.ForEach(item => Console.Write(item));
            Console.WriteLine();
        }

        public static List<int> Zip(List<int> l1, List<int> l2)

        {
            List<int> newList = new List<int>();
            int max = l1.Count;

            if(l2.Count > max)
            {
                max = l2.Count;
            }

            for(int i = 0; i < max; i++)
            {
                if(i < l1.Count)
                {
                    newList.Add(l1[i]);
                }

                if (i < l2.Count)
                {
                    newList.Add(l2[i]);
                }
            }
            
            return newList;

        }

        class ZipList<T>
        {
            public List<T> l { get; set; }

            public ZipList(List<T> l)
            {
                this.l = l;
            }

            public static List<T> operator +(ZipList<T> a, ZipList<T> b)
            {
                // Zip code here
                return null;
            }

            public static List<T> operator -(ZipList<T> a, ZipList<T> b)
            {
                // Unzip code here
                return null;
            }
        }
    }
}