Advent of Code 2024 day004.rb

day004.rb

require_relative "main"

module Day004
  INPUT = File.read('INPUT.txt')

  ##########
  # Part 1 #
  ##########

  grid = INPUT.to_grid

  answer1 = 0
  grid.each do |v|
    [
      [v, v + V[1, 0], v + V[2, 0], v + V[3, 0]],
      [v, v + V[-1, 0], v + V[-2, 0], v + V[-3, 0]],
      [v, v + V[0, 1], v + V[0, 2], v + V[0, 3]],
      [v, v + V[0, -1], v + V[0, -2], v + V[0, -3]],
      [v, v + V[1, 1], v + V[2, 2], v + V[3, 3]],
      [v, v + V[1, -1], v + V[2, -2], v + V[3, -3]],
      [v, v + V[-1, -1], v + V[-2, -2], v + V[-3, -3]],
      [v, v + V[-1, 1], v + V[-2, 2], v + V[-3, 3]],
    ].each do |dir|
      if grid.get_values(dir) == ['X', 'M', 'A', 'S']
        answer1 += 1
      end
    end
  end

  pp answer1

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

  answer2 = 0
  grid.each do |v|
    if [
      ['M', 'S', 'A', 'M', 'S'],
      ['S', 'M', 'A', 'S', 'M'],
      ['M', 'M', 'A', 'S', 'S'],
      ['S', 'S', 'A', 'M', 'M'],
    ].include?(grid.get_values([
      v + V[-1, -1],
      v + V[1, -1],
      v,
      v + V[-1, 1],
      v + V[1, 1],
    ]))
      answer2 += 1
    end
  end

  pp answer2
end