using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void printEnum<T>(IEnumerable<T> enumr) {

        Console.WriteLine(

            string.Join(",", enumr)

            );

    }

    public static IEnumerable<Tuple<bool, T>> GetDifferences<T>(IEnumerable<T> a, IEnumerable<T> b) where T : IComparable

    {

        var enumA = a.GetEnumerator();

        if (!enumA.MoveNext()) {

            foreach(var r in b.Select(i => Tuple.Create(false, i)))

                yield return r;

            yield break;

        }

        var enumB = b.GetEnumerator();

        if (!enumB.MoveNext()) {

            foreach(var r in a.Select(i => Tuple.Create(true, i)))

                yield return r;

            yield break;

        }

        while(true) {

            var currentCompare = enumA.Current.CompareTo(enumB.Current);

            if (currentCompare == 0) {

                if (!enumA.MoveNext()) {

                    while(enumB.MoveNext()) {

                        yield return Tuple.Create(false, enumB.Current);

                    }

                    yield break;

                }

                if (!enumB.MoveNext()) {

                    do {

                        yield return Tuple.Create(true, enumA.Current);

                    } while(enumA.MoveNext());

                    yield break;

                }

            } else if (currentCompare < 0) {

                yield return Tuple.Create(true, enumA.Current);

                if (!enumA.MoveNext()) {

                    do {

                        yield return Tuple.Create(false, enumB.Current);

                    } while(enumB.MoveNext());

                    yield break;

                }

            }

            else {

                yield return Tuple.Create(false, enumB.Current);

                if (!enumB.MoveNext()) {

                    do {

                        yield return Tuple.Create(true, enumA.Current);

                    } while(enumA.MoveNext());

                    yield break;

                }

            }

        }

    }

    public static void Main()

    {

        var examples = new Tuple<List<int>,List<int>>[] {

            Tuple.Create(

                new List<int>() {1,2,3}, 

                new List<int>() {1,4}

            ),

            Tuple.Create(

                new List<int>() {1,2,3}, 

                new List<int>() {1,4,5}

            ),

            Tuple.Create(

                new List<int>() {0}, 

                new List<int>() {1,4,5}

            ),

            Tuple.Create(

                new List<int>() {0}, 

                new List<int>() {0}

            ),

            Tuple.Create(

                new List<int>() {0}, 

                new List<int>() {0,1}

            ),

            Tuple.Create(

                new List<int>() {0,1}, 

                new List<int>() {0}

            ),

            Tuple.Create(

                new List<int>() {}, 

                new List<int>() {1,4,5}

            ),

            Tuple.Create(

                new List<int>() {1,2,3}, 

                new List<int>() {}

            )

        };

        foreach(var t in examples) {

            printEnum(t.Item1);

            printEnum(t.Item2);

            Console.WriteLine("-----");

            printEnum(GetDifferences(t.Item1,t.Item2).Select(i => (i.Item1 ? "add " : "remove ") + i.Item2));

            Console.WriteLine("=================");

        }

    }

}