aoc2025/day_02/2.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

class Main
  def run
    @sum = 0

    line = $stdin.gets.chomp
    line.split(",").each do |range|
      lo, hi = range.split("-")
      (lo..hi).each do |num|
        (1..num.length / 2).each do |n|
          if num.length % n != 0
            next
          end

          parts = num.scan(/(\d{#{n}})/).map { _1[0] }
          if all_equal? parts
            @sum += num.to_i
            break
          end
        end
      end
    end

    puts @sum
  end

  def all_equal?(arr)
    arr.uniq.size <= 1
  end
end

Main.new.run