01. Company Roster

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

namespace _01._Company_Roster
{
    public class Employees
    {
        public Dictionary<string, double> Names { get; set; }
        public double TotalSalary  { get; set; }
        public int Counter { get; set; }
        public double AverageSalary { get; set; }
    }

    class Program
    {
        static void Main()
        {
            int n = int.Parse(Console.ReadLine());

            Dictionary<string, Employees> employees = new Dictionary<string, Employees>();
            for (int i = 0; i < n; i++)
            {
                var input = Console.ReadLine().Split();
                var name = input[0];
                var salary = double.Parse(input[1]);
                var department = input[2];

                if (!employees.ContainsKey(department))
                {
                    var employee = new Employees();
                    employee.Counter = 1;
                    employee.Names = new Dictionary<string, double>();
                    employee.Names.Add(name, salary);

                    employee.TotalSalary += salary;
                    employee.AverageSalary = employee.TotalSalary / employee.Counter;

                    employees[department] = employee;
                }
                else
                {
                    employees[department].Names.Add(name, salary);
                    employees[department].Counter ++;
                    employees[department].TotalSalary += salary;
                    employees[department].AverageSalary = employees[department].TotalSalary / employees[department].Counter;
                }
            }

            employees = employees.OrderByDescending(x => x.Value.AverageSalary).ToDictionary(x => x.Key, y => y.Value);

            foreach (var department in employees)
            {
                Console.WriteLine($"Highest Average Salary: {department.Key}");
                foreach (var name in department.Value.Names.OrderByDescending(x => x.Value))
                {
                    Console.WriteLine($"{name.Key} {name.Value:F2}");
                }
                break;
            }
        }
    }
}