Wiggle Subsequence

class Solution:
    def wiggleMaxLength(self, nums: List[int]) -> int:
        n = len(nums)

        if n == 1:
            return 1

        ans = 1
        prev = nums[0]

        for i in range(1, n-1):
            if (nums[i] > prev and nums[i] > nums[i+1]) or (nums[i] < prev and nums[i] < nums[i+1]):
                ans += 1
                prev = nums[i]

        return ans + int(nums[n-1] != prev)