Given an array, rotate the array to the right by k steps, where k is non-negative.
Follow up:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem. Could you do it in-place with O(1) extra space?
Example 1:
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:
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 <= 2 * 104 -231 <= nums[i] <= 231 - 1 0 <= k <= 105
public class Solution {
public void Rotate(int[] nums, int k) {
k = k % nums.Length;
Reverse(ref nums,0, nums.Length -1 - k);
Reverse(ref nums, nums.Length-k, nums.Length-1);
Reverse(ref nums, 0, nums.Length-1);
}
private void Reverse(ref int[] nums, int start, int end){
for(int i=start, j=end;i<j;i++,j--){
Swap(ref nums,i,j);
}
}
private void Swap(ref int[] nums, int source, int destination){
int temp = nums[source];
nums[source] = nums[destination];
nums[destination] = temp;
}
}Time Complexity: O(n)
Space Complexity: O(1)
