Quicksort

def partition(l):
    pivot = l[0]
    lesser = [x for x in l if x < pivot]
    greater = [x for x in l if x > pivot]
    return (lesser, [pivot], greater)

def quicksort(l):
    if len(l) == 0:
        return []
    lesser, pivot, greater = partition(l)
    return quicksort(lesser) + pivot + quicksort(greater)