189. Rotate Array

Rotate an array of n elements to the right by k steps.

For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].

Hint:
Could you do it in-place with O(1) extra space?

题目大意：旋转一个列表，要求空间复杂度O(1)。

思路：使用Python list 的切片

class Solution(object):    def rotate(self, nums, k):        """        :type nums: List[int]        :type k: int        :rtype: void Do not return anything, modify nums in-place instead.        """        n = len(nums)        k %= n         nums[:] = nums[n-k:] + nums[:n-k]        

nums[:]的作用见这里