# 0978. Longest Turbulent Subarray

https://leetcode.com/problems/longest-turbulent-subarray

## Description

Given an integer array `arr`, return _the length of a maximum size turbulent subarray of_ `arr`.

A subarray is **turbulent** if the comparison sign flips between each adjacent pair of elements in the subarray.

More formally, a subarray `[arr[i], arr[i + 1], ..., arr[j]]` of `arr` is said to be turbulent if and only if:

* For `i <= k < j`:
  * `arr[k] > arr[k + 1]` when `k` is odd, and
  * `arr[k] < arr[k + 1]` when `k` is even.
* Or, for `i <= k < j`:
  * `arr[k] > arr[k + 1]` when `k` is even, and
  * `arr[k] < arr[k + 1]` when `k` is odd.

**Example 1:**

```
**Input:** arr = [9,4,2,10,7,8,8,1,9]
**Output:** 5
**Explanation:** arr[1] > arr[2] < arr[3] > arr[4] < arr[5]
```

**Example 2:**

```
**Input:** arr = [4,8,12,16]
**Output:** 2
```

**Example 3:**

```
**Input:** arr = [100]
**Output:** 1
```

**Constraints:**

* `1 <= arr.length <= 4 * 104`
* `0 <= arr[i] <= 109`

## ac

```java
```
