6b.rb

class Coordinate

  attr_accessor :id, :x, :y, :area, :blacklisted

  def initialize(x, y, id)
    @id = id
    @x = x
    @y = y
    @area = 0
    @blacklisted = false
  end

end

ids = [*'a'..'z', *'A'..'Z']

coordinates = File.read('input.txt').each_line.map do |line|
  x, y = line.split(', ').map(&:to_i)
  Coordinate.new(x, y, ids.shift)
end

max_x = coordinates.max_by(&:x).x
max_y = coordinates.max_by(&:y).y

region_area = 0
(0..max_y).each do |y|
  (0..max_x).each do |x|
    total_distance = coordinates.map {|coordinate| (coordinate.x - x).abs + (coordinate.y - y).abs}.inject(:+)
    region_area += 1 if total_distance < 10_000
  end
end

puts "Region area: #{region_area}"