qs.py

"""
An exampe quicksort implementation, demonstrating pythonic style 
(albeit using inefficient `+` to concatenate lists...)
"""
def quicksort(seq):
    if len(seq) <= 1:
        return seq
    pivot, *rest = seq
    smaller = quicksort([x for x in rest if x <= pivot])
    larger = quicksort([x for x in rest if x > pivot])
    return smaller + [pivot] + larger