From: Levin Alexander <levin@...>
Date: 2005-12-05T01:29:33+09:00
Subject: Re: [QUIZ] Weird Numbers (#57) Solution

On 12/4/05, Simon Strandgaard <neoneye@gmail.com> wrote:
Here is my solution.<http://tinyurl.com/9qjfg> (needs data-url support in your browser)
I basically used the definition of a "weird number" to implement thesolution.  This makes the code pretty, but also really, really slow.
---
#!/usr/bin/ruby
# Rubyquiz #57 -- Weird Numbers# -----------------------------# Levin Alexander <levin@grundeis.net>
module Enumerable  def sum    inject(0) {|s,elem| s+elem}  endend
class Array  def subsets    (0...2**length).collect {|i|       values_at(*(0...length).find_all {|j| i&(1<<j)>0 })    }  endend
class Integer  def abundant?    divisors.sum > self  end
  def semiperfect?    divisors.subsets.any? { |set| set.sum == self }  end
  def weird?    abundant? and not semiperfect?  end
  def divisors    (1...self).select { |i| self % i == 0 }  endend
if __FILE__ == $0  0.upto(ARGV[0].to_i) { |i|    if i.weird?      puts i    else      warn "#{i} is not weird" if $DEBUG    end  }end