【问题描述】
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.
Related problem: Reverse Words in a String II
【思路1】
三次反转,1:反转前部分,2:反转后部分,3:整个反转。
复杂度相对较高
【code】
- public class Solution {
- public void rotate(int[] nums, int k) {
- int temp = k % nums.length;
- reverse(nums, 0, nums.length - temp - 1);
- reverse(nums, nums.length - temp, nums.length - 1);
- reverse(nums, 0, nums.length - 1);
- }
- private void reverse(int[] nums, int start, int end) {
- for (int i = start, j = end; i < j; i++, j--) {
- int temp = nums[i];
- nums[i] = nums[j];
- nums[j] = temp;
- }
- }
- }