Advent of Code 2024 day011.rb

day011.rb

require_relative "main"

module Day011
  INPUT = File.read("INPUT.txt")

  s = INPUT.split.map { [_1.to_i, 1] }.to_h

  convert = ->(n) do
    return [1] if n == 0
    t = n.to_s
    ll = t.length / 2
    t.length.even? ? [t[0...ll].to_i, t[ll..].to_i] : [n * 2024]
  end

  75.times do |i|
    s = s.each_with_object(Hash.new { |h, k| h[k] = 0 }) do |(k, v), a|
      convert.call(k).each { a[_1] += v }
    end

    # Part 1
    if i == 24
      answer1 = s.values.sum

      pp answer1
    end
  end

  # Part 2
  answer2 = s.values.sum

  pp answer2
end