From: Levin Alexander <levin@...>
Date: 2005-12-05T09:28:50+09:00
Subject: Re: Weird Numbers (#57) Solution

On 12/4/05, Christer Nilsson <janchrister.nilsson@gmail.com> wrote:
> The part I appreciate most is the beautiful and fast handling of the> binary set:>>   def sum_in_subset?(a)>     if self < 0>       false>     elsif a.include?(self)>       true>     else>       if a.length == 1>         false>       else>         f = a.first>         remaining = a[1..-1]>         (self - f).sum_in_subset?(remaining) or>                    sum_in_subset?(remaining)>       end>     end>   end
Yes, this is quite nice.  I rewrote it a bit so that it does not needthe nested ifs.  What do you think?
  def sum_in_subset?(div = self.divisors)    return false if self < 0    return false if div.empty?    return true if div.include?(self)
    f, remaining = div[0], div[1..-1]    (self - f).sum_in_subset?(remaining) or sum_in_subset?(remaining)  end

Viele Gr����e,Levin