06. Courses - C# Fundamentals

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

namespace _06._Courses
{
    class Courses
    {
        static void Main()
        {
            Dictionary<string, List<string>> dictCourses = new Dictionary<string, List<string>>();


            string command = Console.ReadLine();
            while (command != "end")
            {
                string[] currentCommand = command.Split(" : ").ToArray();

                string courseName = currentCommand[0];
                string studnetName = currentCommand[1];

                if (!dictCourses.ContainsKey(courseName))
                {
                    dictCourses[courseName] = new List<string>();

                    dictCourses[courseName].Add(studnetName);
                }
                else
                {
                    dictCourses[courseName].Add(studnetName);
                }

                command = Console.ReadLine();
            }

            dictCourses = dictCourses
                          .OrderByDescending(x => x.Value.Count())
                          .ToDictionary(x => x.Key, x => x.Value);


            foreach (var student in dictCourses)
            {
                Console.WriteLine($"{student.Key}: {student.Value.Count()}");

                student.Value.Sort();

                for (int i = 0; i < 1; i++)
                {
                    Console.WriteLine($"-- {string.Join("\n-- ", student.Value)}");
                }

            }

        }
    }
}