Maximum Alternating Subsequence Sum

lcpy gen -n 1911   # by problem number
lcpy gen -s maximum_alternating_subsequence_sum   # by problem name

Input: nums = [4,2,5,3]
Output: 7
Explanation: It is optimal to choose the subsequence [4,2,5] with alternating sum (4 + 5) - 2 = 7.

Input: nums = [5,6,7,8]
Output: 8
Explanation: It is optimal to choose the subsequence [8] with alternating sum 8.

Input: nums = [6,2,1,2,4,5]
Output: 10
Explanation: It is optimal to choose the subsequence [6,1,5] with alternating sum (6 + 5) - 1 = 10.

class Solution:
    # Time: O(n)
    # Space: O(1)
    def max_alternating_sum(self, nums: list[int]) -> int:
        even = 0
        odd = 0
        for num in nums:
            even, odd = max(even, odd + num), max(odd, even - num)
        return even