python希尔排序的使用原理

def shll_sort(alist):

n = len(alist)

gap = n//2 #定义初始步长，要取整数，否则下面for循环会报错'float' object cannot be interpreted as an integer

while gap>0:#按步长进行插入排序

for i in range(gap,n):

j = i

while j>=gap and alist[j-gap]>alist[j]:

alist[j-gap],alist[j]=alist[j],alist[j-gap]

j=j-gap

gap = gap//2#得到新的步长,注意是在while后面的缩进