python实现快速排序

受Haskell的快排启发

qsort :: [Int] -> [Int]
qsort [] = []
qsort (pivot:others) = (qsort lowers) ++ [pivot] ++ (qsort highers)
    where lowers  = filter (<pivot)  others
          highers = filter (>=pivot) others

尝试了用python实现：

def qsort(lst):
    if not lst:
        return []
    pivot = lst[0]
    sub_lst = lst[1:]
    return qsort(lower_elements(pivot, sub_lst))+[pivot]+qsort(highter_elements(pivot, sub_lst))


def lower_elements(pivot,lst):
    return [x for x in lst if x < pivot]


def highter_elements(pivot, lst):
    return [x for x in lst if x >= pivot]

使用python实现更容易理解了(:зゝ∠)