lightbulb.rb

lightbulb.rb

#!/usr/bin/env ruby

def toggle(i)
  i == 0 ? 1 :0
end

# turn on every bulb
bulbs = Array.new 100, 1

# Turn off every x bulb
(2..100).each do |i|
  bulbs.each_with_index do |bulb, index|
    bulb_num = index + 1
    bulbs[index] = toggle(bulbs[index]) if bulb_num % i == 0
  end
end

# find bulb with light still on
bulbs.each_with_index do |bulb, index|
  puts index + 1 if bulbs[index] == 1
end