665. Non-decreasing Array-非递减数列

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 can’t get a non-decreasing array by modify at most one element.

Constraints:

• n == nums.length
• 1 <= n <= 10^4
• -10^5 <= nums[i] <= 10^5

Solution in python:

class Solution:
    def checkPossibility(self, nums: List[int]) -> bool:
        if len(nums) == 1:
            return True
        i = 0
        count = 0
        while i < len(nums)-1:
            if nums[i] <= nums[i+1]:
                i += 1    
            else:
                count += 1
                if count >= 2:
                    return False
                i += 1
        for i in range(len(nums)):
            temp = nums[::]
            temp.pop(i)
            j = 0
            while j < len(temp)-1:
                if temp[j] <= temp[j+1]:
                    j += 1
                else:
                    break
            if j == len(temp)-1:
                return True
        return False