Valid Mountain Array Python Solution

lcpy gen -n 941   # by problem number
lcpy gen -s valid_mountain_array   # by problem name

Input: arr = [2,1]
Output: false

Input: arr = [3,5,5]
Output: false

Input: arr = [0,3,2,1]
Output: true

class Solution:
    # Time: O(n)
    # Space: O(1)
    def valid_mountain_array(self, arr: list[int]) -> bool:
        i = 0
        n = len(arr)
        while i + 1 < n and arr[i] < arr[i + 1]:
            i += 1
        if i == 0 or i == n - 1:
            return False
        while i + 1 < n and arr[i] > arr[i + 1]:
            i += 1
        return i == n - 1