advent-of-code-2024/25/main.rb

#!/usr/bin/env ruby

class Component < Array
  def self.from_line(line)
    new(line.map(&:chars)[1..-2].transpose.map { _1.count("#") })
  end
end

class Lock < Component
  def accepts?(key) = zip(key).all? { _1.sum <= 5 }
end

Key = Class.new(Component)

def create(line)
  (line.first == "#####" ? Lock : Key).from_line(line)
end

input = (ARGV.first.nil? ? DATA : ARGF)
  .readlines(chomp: true)
  .slice_when { |a, b| b.empty? }
  .map { _1.reject { |a| a.empty? } }
  .map(&method(:create))

locks, keys = input.partition { _1.is_a?(Lock) }

p locks.sum { |lock| keys.count { lock.accepts?(_1) } }


__END__
#####
.####
.####
.####
.#.#.
.#...
.....

#####
##.##
.#.##
...##
...#.
...#.
.....

.....
#....
#....
#...#
#.#.#
#.###
#####

.....
.....
#.#..
###..
###.#
###.#
#####

.....
.....
.....
#....
#.#..
#.#.#
#####