Advent of Code 2024 day013.rb

day013.rb

require_relative "main"

module Day013
  INPUT = File.read("INPUT.txt")

  answer1 = 0
  answer2 = 0

  INPUT.split("\n\n").each do |group|
    ax, ay, bx, by, px1, py1 = group.split("\n").map { |line| line.split(",").map { |s| s[/\d+/].to_i } }.flatten

    a1 = (px1 * by - py1 * bx).to_f / (by * ax - ay * bx)
    b1 = (py1 - a1 * ay).to_f / by

    if a1.to_i == a1 && b1.to_i == b1 && a1 <= 100 && b1 <= 100
      answer1 += (3 * a1 + b1).to_i
    end

    px2 = px1 + 10_000_000_000_000
    py2 = py1 + 10_000_000_000_000

    a2 = (px2 * by - py2 * bx).to_f / (by * ax - ay * bx)
    b2 = (py2 - a2 * ay).to_f / by

    if a2.to_i == a2 && b2.to_i == b2
      answer2 += (3 * a2 + b2).to_i
    end
  end

  pp answer1
  pp answer2
end