快速排序

普通版

def quick_sort(array, left, right):
    if left >= right:
        return
    low = left
    high = right
    key = array[low]
    while left < right:
        while left < right and array[right] > key:
            right -= 1
        array[left] = array[right]
        while left < right and array[left] <= key:
            left += 1
        array[right] = array[left]
    array[right] = key
    quick_sort(array, low, left - 1)
    quick_sort(array, left + 1, high)

简单版

def quick_sort(arr):
　　if len(arr) <= 1:
　　　　return arr
　　pivot = arr[len(arr) // 2]
　　left = [x for x in arr if x < pivot]
　　middle = [x for x in arr if x == pivot]
　　right = [x for x in arr if x > pivot]
　　return quick_sort(left) + middle + quick_sort(right)