排序算法-希尔排序

def shell_sort(arr):
    n = len(arr)
    gap = n // 2
    while gap > 0:
        for i in range(gap, n):
            j = i
            while j > 0:
                if arr[j] > arr[j-gap]:
                    arr[j], arr[j-gap] = arr[j-gap], arr[j]
                    j-= gap
                else:
                    break

        gap /= 2