05. Book Library

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

namespace _05.BookLibrary
{
    class Program
    {
        static void Main(string[] args)
        {
            int iteration = int.Parse(Console.ReadLine());

            List<Book> books = new List<Book>();

            Library library = new Library("Library", books);

            for (int i = 0; i < iteration; i++)
            {
                books.Add(ReadBook());
            }

            Console.WriteLine(library);
        }

        private static Book ReadBook()
        {
            string[] input = Console.ReadLine().Split().ToArray();

            return new Book(input[0], input[1], input[2],
                            DateTime.ParseExact(input[3], "dd.MM.yyyy", CultureInfo.InvariantCulture),
                            input[4], double.Parse(input[5]));
        }
    }
  class Book
    {
        public string Title { get; set; }
        public string Author { get; set; }
        public string Publisher { get; set; }
        public DateTime ReleaseDate { get; set; }
        public string ISBN { get; set; }
        public double Price { get; set; }

        public Book(string title, string author, string publisher, DateTime releaseDate, string ISBN, double price)
        {
            this.Title = title;
            this.Author = author;
            this.Publisher = publisher;
            this.ReleaseDate = releaseDate;
            this.ISBN = ISBN;
            this.Price = price;
        }
    }
  class Library
    {
        public string Name { get; set; }
        public List<Book> Books { get; set; }

        public Library(string name, List<Book> books)
        {
            this.Name = name;
            this.Books = books;
        }

        public override string ToString()
        {
            Dictionary<string, double> result = new Dictionary<string, double>();
            foreach (Book item in Books)
            {
                if(!result.ContainsKey(item.Author))
                {
                    result.Add(item.Author, item.Price);
                }
                else
                {
                    result[item.Author] += item.Price;
                }
            }
            string final = string.Join(Environment.NewLine, result.OrderByDescending(x => x.Value).ThenBy(x => x.Key).Select(x => new string($"{x.Key} -> {x.Value:f2}".ToCharArray())).ToArray());
            return final;
        }
    }
}