gistfile1.rb

class Quick
   def self.sort(array)
     return array if array.size < 2
     lesser = []
     greater = []
     pivot = array.pop
     array.each do |x|
       x <= pivot ? lesser << x : greater << x
     end
     self.sort(lesser) + [pivot]+ self.sort(greater)
  end
end

gistfile2.rb

class Quick
  def self.sort(array)
    return array if array.size < 2
    pivot = array.pop
    array = array.partition { |x| x <= pivot }
    self.sort(array.first) + [pivot] + self.sort(array.last)
  end
end