Longest Turbulent Subarray

978. Longest Turbulent Subarray

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:

  <ul>
  	<li><code>arr[k] &gt; arr[k + 1]</code> when <code>k</code> is odd, and</li>
  	<li><code>arr[k] &lt; arr[k + 1]</code> when <code>k</code> is even.</li>
  </ul>
  </li>
  <li>Or, for <code>i &lt;= k &lt; j</code>:
  <ul>
  	<li><code>arr[k] &gt; arr[k + 1]</code> when <code>k</code> is even, and</li>
  	<li><code>arr[k] &lt; arr[k + 1]</code> when <code>k</code> is odd.</li>
  </ul>
  </li>
  

 

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