189. Rotate Array

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

• 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`

189. Rotate Array
``````struct Solution;

impl Solution {
fn rotate(nums: &mut Vec<i32>, k: i32) {
let k = k as usize % nums.len();
nums[..].reverse();
nums[0..k].reverse();
nums[k..].reverse();
//      nums.rotate_right(k);
}
}

#[test]
fn test() {
let mut nums = vec![1, 2, 3, 4, 5, 6, 7];
Solution::rotate(&mut nums, 3);
assert_eq!(nums, vec![5, 6, 7, 1, 2, 3, 4]);
}
``````