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].

Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

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

思路

利用Python语言对于list操作的性质，可以得到空间复杂度为O(1)的结果。

1
2
3
4
5
6
7
8
9
10
11
12
13
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.
        """
        length = len(nums)
        if (k > length):
            k = k % length
        for i in range(length - k):
            nums.append(nums[0])
            del nums[0]