Advent of Code 2023 Day 2

day_two.rb

#!/usr/bin/env ruby

INPUT_FILE = 'part_one.input'

View = Data.define(:r, :g, :b) do
  REGEX = /(\d+) red|(\d+) green|(\d+) blue/

  def total     = r + g + b
  def power     = r * g * b
  def +(o)      = self.class[r + o.r, g + o.g, b + o.b]
  def self.zero = self[0, 0 ,0]

  def self.parse(string)
    string.scan(REGEX).reduce(self.zero) do |sum, (r, g, b)|
      sum + new(r: r.to_i, g: g.to_i, b: b.to_i)
    end
  end

  def possible?(bag)
    !(total > bag.total || r > bag.r || g > bag.g || b > bag.b)
  end

  def smoosh(o)
    self.class[
      (r > o.r) ? r : o.r,
      (g > o.g) ? g : o.g,
      (b > o.b) ? b : o.b
    ]
  end
end

Game = Data.define(:id, :views) do
  def self.parse(string)
    _, id, body = string.match(/Game (\d+): (.+)/).to_a
    views = body.split(';').map { |view| View.parse(view) }
    self.new(id: id.to_i, views: views)
  end

  def possible?(bag)
    views.all? { |view| view.possible?(bag) }
  end
end


bag = View[12, 13, 14]
games = File.read(INPUT_FILE).split("\n").map do |line|
  Game.parse(line)
end

possible = games.select { |game| game.possible?(bag) }

puts "The sum of possible game ids is #{possible.map(&:id).sum}"


sum = games.map do |game|
  game.views.reduce(View.zero) do |sum, view|
    sum.smoosh(view)
  end.power
end.sum

puts "The sum of the power of smooshed sets is #{sum}"