name = 'quick_sort/2'
slug = 'sort a list using quicksort'

description = '''\
<p><code>quick_sort(L, SL)</code>: the list <code>SL</code> contains the elements of <code>L</code> sorted in non-decreasing order. Use the predicate <code>pivoting/4</code> to implement quicksort.</p>
<pre>
?- quick_sort([2,3,1,5,4], L).
  L = [1,2,3,4,5].
</pre>'''

hint = {}