# 0643. Maximum Average Subarray I

<https://leetcode.com/problems/maximum-average-subarray-i>

## Description

You are given an integer array `nums` consisting of `n` elements, and an integer `k`.

Find a contiguous subarray whose **length is equal to** `k` that has the maximum average value and return *this value*. Any answer with a calculation error less than `10-5` will be accepted.

**Example 1:**

```
**Input:** nums = [1,12,-5,-6,50,3], k = 4
**Output:** 12.75000
**Explanation:** Maximum average is (12 - 5 - 6 + 50) / 4 = 51 / 4 = 12.75
```

**Example 2:**

```
**Input:** nums = [5], k = 1
**Output:** 5.00000
```

**Constraints:**

* `n == nums.length`
* `1 <= k <= n <= 105`
* `-104 <= nums[i] <= 104`

## ac

```java
```