665. Non-decreasing Array

https://leetcode.com/problems/non-decreasing-array/

Python

class Solution:
    def checkPossibility(self, nums: List[int]) -> bool:
        if len(nums) <= 2:
            return True

        is_modified = False

        for i in range(1, len(nums)):
            left, right = nums[i-1], nums[i]
            
            if left <= right:
                continue

            if is_modified:
                return False
            
            is_modified = True
            
            if i < 2 or nums[i-2] <= nums[i]:
                nums[i-1] = nums[i]
            else:
                nums[i] = nums[i-1]

        return True