Functional Programming - 11. The Party Reservation Filter Mo

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

namespace Advanced
{
    class Program
    {
        static void Main(string[] args)
        {
            var guests = Console.ReadLine().Split().ToList();

            Func<string, string, bool> startsWith = (a, b) => a.StartsWith(b);
            Func<string, string, bool> endsWith = (a, b) => a.EndsWith(b);
            Func<string, string, bool> contains = (a, b) => a.Contains(b);
            Func<string, int, bool> checkLength = (a, b) => a.Length == b;

            List<string> result = new List<string>(guests);
            List<string> filtered = new List<string>();

            while (true)
            {
                var input = Console.ReadLine();

                if (input == "Print")
                {
                    break;
                }

                var line = input.Split(";");

                var command = line[0];
                var action = line[1];
                var criteria = line[2];

                switch (action)
                {
                    case "Starts with":
                        filtered = guests.Where(i => startsWith(i, criteria)).ToList();
                        break;

                    case "Ends with":
                        filtered = guests.Where(i => endsWith(i, criteria)).ToList();
                        break;

                    case "Length":
                        filtered = guests.Where(i => checkLength(i, int.Parse(criteria))).ToList();
                        break;

                    case "Contains":
                        filtered = guests.Where(i => contains(i, criteria)).ToList();
                        break;
                }

                switch (command)
                {
                    case "Add filter":
                        result.RemoveAll(r => filtered.Contains(r));
                        break;

                    case "Remove filter":
                        result.AddRange(filtered);
                        result = result.ToList();
                        break;
                }
            }

            guests.RemoveAll(g => !result.Contains(g));
            Console.WriteLine(String.Join(" ", guests));
        }
    }

}