상상할 수 있는 힘이 모자라다

Four Boxes (I translated this quest from http://xper.org/wiki/seminar/FourBoxes) Quest There are four rectangles in plan and all their base of four rectangles are in parallel with the horizontal ...

def sum_of_divisors(num)   divisors = [1]   (2..Math::sqrt(num)).each do |e|     if num % e == 0       divisors << e    &n...