プログラマ脳を鍛える数学パズル：Q03

puzzle03.rb

# -- 処理時間計測の自作ライブラリ --
require './process_measure.rb'
# ------------------------------

def reverse_card_open(card_num)
  cards = Array.new(card_num, false)

  1.upto(card_num) do |i|
    i.step(card_num, i+1) do |j|
      cards[j] = !cards[j]
    end
  end

  card_num.times do |i|
    print "#{i + 1} " if cards[i] == false
  end
end

measure_do { reverse_card_open(100) }