189. Rotate Array

Posted on Edited on In

189. Rotate Array

Description

Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.

Example 1:

1
2
3
4
5
6
Input: nums = [1,2,3,4,5,6,7], k = 3
Output: [5,6,7,1,2,3,4]
Explanation:
rotate 1 steps to the right: [7,1,2,3,4,5,6]
rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]

Example 2:

1
2
3
4
5
Input: nums = [-1,-100,3,99], k = 2
Output: [3,99,-1,-100]
Explanation:
rotate 1 steps to the right: [99,-1,-100,3]
rotate 2 steps to the right: [3,99,-1,-100]

Constraints:

  • 1 <= nums.length <= 10^5
  • -2^31 <= nums[i] <= 2^31 - 1
  • 0 <= k <= 10^5

Follow up:

  • Try to come up with as many solutions as you can. There are at least three different ways to solve this problem.
  • Could you do it in-place with O(1) extra space?

Hints/Notes

Solution

Language: C++

1
2
3
4
5
6
7
8
9
10
class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        k %= nums.size();
        k = nums.size() - k;
        reverse(nums.begin(), nums.begin() + k);
        reverse(nums.begin() + k, nums.end());
        reverse(nums.begin(), nums.end());
    }
};