# Rotate array by K steps

## Simplify Rotation Amount

For an array of sized $$n$$ instead of doing $$K$$ rotation 

$$
K = n + n + n + ... + x
$$

we can simply do $$K%n$$ rotation

$$
x = K%n
$$

If we rotate $$K$$steps to right we need to start reading the rotated array from the last $$K%n$$elements.

If we rotate $$K$$steps to left we need to start reading the rotated array after skipping $$K%n$$elements from start

## Rotation

### Complexity

* **Time complexity** : $$\text{O}(n)$$
  * We iterate the whole array only once
* **Space complexity** : $$\text{O}(1)$$
  * No extra space is needed

### Code

```java
public void rotate(int[] nums, int k) { 
	k %= nums.length; 
	reverse(nums, 0, nums.length - 1); 
	reverse(nums, 0, k - 1); 
	reverse(nums, k, nums.length - 1); 
}

public void reverse(int[] nums, int start, int end) { 
	while (start < end) { 
		int temp = nums[start]; 
		nums[start] = nums[end]; 
		nums[end] = temp; 
		start++; 
		end--; 
	} 
}
```


---

# Agent Instructions: 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:

```
GET https://private-26.gitbook.io/notes/algorithmic-pattern/miscellaneous/rotate-array-by-k-steps.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.