07. Company Users

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

namespace CompanyUsers
{
    class Program
    {
        public static void Main()
        {
            Dictionary<string, List<string>> companies = new Dictionary<string, List<string>>();

            string command;

            while ((command = Console.ReadLine()) != "End")
            {
                string[] current = command.Split(" -> ");

                string company = current[0];
                string employeeID = current[1];

                if (!companies.ContainsKey(company))
                {
                    companies.Add(company, new List<string>());
                }

                if (!companies[company].Contains(employeeID))
                {
                    companies[company].Add(employeeID);
                }
            }

            foreach (var company in companies)
            {
                Console.WriteLine($"{company.Key}\n-- {string.Join("\n-- ", company.Value)}");
            }
        }
    }
}