[LeetCode]Rotate Array

public class Solution {
    public void rotate(int[] nums, int k) {
        int length = nums.length;
        k = k % length;
        reverse(nums, 0, length - 1);
        reverse(nums, 0, k - 1);
        reverse(nums, k, length - 1);
    }
    public void reverse(int[] nums, int left, int right) {
        while (left < right) {
            int tmp = nums[left];
            nums[left] = nums[right];
            nums[right] = tmp;
            left ++;
            right --;
        }
    }
}

 慢速方法

public class Solution {
    public void rotate(int[] nums, int k) {
        int length = nums.length;
        k = k % length;
        if (k == 0) {
            return;
        }
        int[] record = new int[k];
        int ind = 0;
        for (int i = length - k; i < length; i++) {
            record[ind++] = nums[i];
        }
        for (int i = length - 1; i >= k; i--) {
            nums[i] = nums[i - k];
        }
        for (int i = 0; i < k; i++) {
            nums[i] = record[i];
        }
    }
}