My Solution for Shopify’s Day 1 Challenge at RubyConf 2022

shopify_day_1_challenge.rb

require 'csv'
require 'json'

def produce_song_list_from_song_entries(song_entries)
  song_entries
  .map { |_, _, song, size| [File.basename(song), size.to_i] }
  .sort_by { |song, size| size }
  .reverse
end

Album = Struct.new(:size, :songs)
def albums_from_song_list(song_list)
  albums = []
  if !song_list.empty?
    albums << Album.new(0, [])
  end
  song_list.each do |song|
    song_name, song_size = song
    found_spot_in_album = false
    albums.each do |album|
      if album.size + song_size <= 122_880
        found_spot_in_album = true
        album.songs << song
        album.size += song_size
        break
      end
    end
    unless found_spot_in_album
      albums << Album.new(song_size, [song])
    end
  end
  return albums.map(&:songs)
end

# songs = CSV.parse(File.read("rows_of_sweet_jams.csv"), headers: true).to_a[1..-1]

songs_enumerator = Enumerator.new do |e|
  CSV.foreach("rows_of_sweet_jams.csv") { |r| e.yield r.to_a } 
end

sites_to_song_entries = 
  songs_enumerator
  .lazy
  .group_by { |entry| entry.first }
  .map { |site, song_entries| 
    [
      site, 
      produce_song_list_from_song_entries(song_entries)
      .then { |song_list| albums_from_song_list(song_list) }
    ] 
  }
  .to_h
  .to_json

puts sites_to_song_entries