Advent of Code 2024 day014.rb

day014.rb

require_relative "main"

module Day014
  INPUT = File.read("INPUT.txt")
  WIDTH = 101
  HEIGHT = 103

  rs = INPUT.split("\n").map do |line|
    line.split(" ").map do |chunk|
      V[*chunk.split("=").last.split(",").map(&:to_i)]
    end
  end

  mean_density = 1
  j = 0

  loop do
    j += 1
    grid = Grid.new(WIDTH, HEIGHT, 0)

    rs.each_with_index do |(pos, v), i|
      pos += v
      pos.x %= WIDTH
      pos.y %= HEIGHT
      rs[i][0] = pos
      grid.set_value(pos, 1)
    end

    density = rs.sum { |(pos, _v)| grid.get_values(grid.nine(pos)).sum }

    mean_density = (j == 1) ? density : ((j - 1) * mean_density + density) / j
    break if density > 3 * mean_density

    if j == 100
      ##########
      # Part 1 #
      ##########

      x_left, x_right = 0...WIDTH / 2, WIDTH / 2 + 1..WIDTH - 1
      y_top, y_bottom = 0...HEIGHT / 2, HEIGHT / 2 + 1..HEIGHT - 1

      qs = [
        [x_right, y_top],
        [x_left, y_top],
        [x_left, y_bottom],
        [x_right, y_bottom]
      ]

      answer1 = qs.reduce(1) do |m, q|
        m * rs.count { |(pos, _v)| q.first === pos.x && q.last === pos.y }
      end

      pp answer1
    end
  end

  ##########
  # Part 2 #
  ##########

  answer2 = j

  pp answer2
end