/8/quicksort.rb

class Array
  def qsort
    return self if self.length <= 1
    pivot = self.shift
    left, right = [],[]
    self.each { |ele| ele <= pivot ? left << ele : right << ele }
    left.qsort + [pivot] + right.qsort
  end
end

# Example of use
# p t[8,6,544,423,3].qsort