class Solution:
    def checkPossibility(self, nums: List[int]) -> bool:
        cnt = 0
        if len(nums) <= 1: return True
        for i in range(1, len(nums)):
            if nums[i-1] > nums[i]:
                if cnt > 0 or 1 < i < len(nums)-1 and nums[i-2] > nums[i] and nums[i+1] < nums[i-1]:
                    return False
                cnt += 1
        return True


#  -2  -1  i  +1
#   7  10  5         -> can't decrease i-1     nums[i-2] > nums[i]
#   7  10  5   3     -> can't increase i+1     nums[i+1] < nums[i-1]