> For the complete documentation index, see [llms.txt](https://hannahpun.gitbook.io/leetcode-note/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hannahpun.gitbook.io/leetcode-note/array/189-rotate-array.md).

# # 189 Rotate Array

[LeetCode](https://leetcode.com/problems/rotate-array/)

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

```
Example 1:

Input: [1,2,3,4,5,6,7] and 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: [-1,-100,3,99] and 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]
Note:

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?

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {void} Do not return anything, modify nums in-place instead.
 */
var rotate = function(nums, k) {}
```

### 怎麼解

會用 % 餘數，然後用移掉後面的接回來前面

```
var rotate = function(nums, k) {
  k = k%nums.length;
  
  for(let i = 0; i < nums.length - k; i++) {
      nums.push(nums.shift())
  }
  return nums
  
};
```

better

```javascript

let len = nums.length;
let newArr = new Array(len-1)
    

 for(let i=0; i<len ; i++){
     const newIndex = i + k;
     if(newIndex < len){
        newArr[newIndex] = nums[i];
     } else {
        newArr[newIndex%len] = nums[i];
     }
        
}

for(let i=0; i<len ; i++){
    nums[i] = newArr[i]
}

```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://hannahpun.gitbook.io/leetcode-note/array/189-rotate-array.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.