Wiggle Subsequence Python Solution with Tests

lcpy gen -n 376   # by problem number
lcpy gen -s wiggle_subsequence   # by problem name

Input: nums = [1,7,4,9,2,5]
Output: 6
Explanation: The entire sequence is a wiggle sequence with differences (6, -3, 5, -7, 3).

Input: nums = [1,17,5,10,13,15,10,5,16,8]
Output: 7
Explanation: There are several subsequences that achieve this length.
One is [1, 17, 10, 13, 10, 16, 8] with differences (16, -7, 3, -3, 6, -8).

Input: nums = [1,2,3,4,5,6,7,8,9]
Output: 2

class Solution:
    # Time: O(n)
    # Space: O(1)
    def wiggle_max_length(self, nums: list[int]) -> int:
        up = down = 1
        for i in range(1, len(nums)):
            if nums[i] > nums[i - 1]:
                up = down + 1
            elif nums[i] < nums[i - 1]:
                down = up + 1
        return max(up, down)