roliCoder2

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

namespace rolicoder
{
    class Program
    {
        class Event
        {
            public string Name { get; set; }
            public List<string> Participants { get; set; }

            public Event(string name, List<string> participants)
            {
                Name = name;
                Participants = participants;
            }
        }
        static void Main(string[] args)
        {
            Dictionary<long, Event> events = new Dictionary<long, Event>();
            string input = Console.ReadLine();
            string pattern = @"^(?<id>[\d]+) #(?<name>[\w]+)(?<participants>[ ?@\w]*)$";
            while (input != "Time for Code")
            {
                Match currMatch = Regex.Match(input, pattern);
                long id = long.Parse(currMatch.Groups["id"].Value);
                string eventName = currMatch.Groups["name"].Value;
                List<string> participants = new List<string>(currMatch.Groups["participants"].Value
                    .Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries)
                    .ToList());
                if (!events.ContainsKey(id))
                {
                    events.Add(id, new Event(eventName, participants));
                }
                else
                {
                    if (events[id].Name == eventName)
                    {
                        for (int i = 0; i < participants.Count; i++)
                        {
                            if (!events[id].Participants.Contains(participants[i]))
                            {
                                events[id].Participants.Add(participants[i]);
                            }
                        }
                    }
                }
                input = Console.ReadLine();
            }

            var orderedEvents = events
                .OrderByDescending(oe => oe.Value.Participants.Count())
                .ThenBy(oe => oe.Value.Name);

            foreach (var orderedEvent in orderedEvents)
            {
                Console.WriteLine("{0} - {1}", orderedEvent.Value.Name, orderedEvent.Value.Participants.Count());
                foreach (var participant in orderedEvent.Value.Participants.OrderBy(oe => oe))
                {
                    Console.WriteLine(participant);
                }
            }
        }
    }
}