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

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