665 Non-decreasing Array

Given an array nums with n integers, your task is to check if it could become non-decreasing by modifying at most one element.

We define an array is non-decreasing if nums[i] <= nums[i + 1] holds for every i (0-based) such that (0 <= i <= n - 2).

Example 1:

Input: nums = [4,2,3]
Output: true
Explanation: You could modify the first 4 to 1 to get a non-decreasing array.

Example 2:

Input: nums = [4,2,1]
Output: false
Explanation: You cannot get a non-decreasing array by modifying at most one element.

Constraints:

• n == nums.length
• 1 <= n <= 104
• -104 <= nums[i] <= 105

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