Maximum Length Sequence with Two Increasing-Decreasing Transitions

amazon Question 2: Construct Monotonic Sequence Given an integer array, construct a sequence that can be increasing, then decreasing, then increasing again, and decreasing again. Use the maximum number of numbers possible. Input: An integer array nums. Output: Return the maximum length of the sequence that can be formed. Example: nums = [1, 2, 3, 4, 5, 6, 7, 8, 9] Output: 9 Example Input 1,2,2,3,3,3,4,4,5