# Problem

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.

[show hint]

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

# Python3

``````# 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.
#
# [show hint]
#
# Hint:
# Could you do it in-place with O(1) extra space?
# Related problem: Reverse Words in a String II

# author li.hzh
class Solution:
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)
k = k % length
if length <= 1 or k == 0:
return
end_index = length - 1
for i in range(length):
temp = nums[i]
current_end = end_index - i
if i < current_end:
nums[i] = nums[current_end]
nums[current_end] = temp
else:
break
for i in range(k):
temp = nums[i]
current_end = k - i - 1
if i < current_end:
nums[i] = nums[current_end]
nums[current_end] = temp
else:
break
for i in range(k, length):
temp = nums[i]
current_end = end_index - i + k
if i < current_end:
nums[i] = nums[current_end]
nums[current_end] = temp
else:
return

solution = Solution()
nums = [1, 2, 3]
solution.rotate(nums, 1)
print(nums)

``````

Thanks a lot.