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).


'''
'''
#Here consider case 2,2,1

if we just check pairs and when we find inflection point(violate increasing) if we change inflection point to right most
element like here inflection happens at index 1 and if we change it becomes [2,1, 1] which is not sorted.
So we should instead pass present element to next element [2,2,2] (when you dont have choice of nums[i-1]<=nums[i+1] ) .
See code for clarity with this example.
'''
class Solution:
    def checkPossibility(self, nums: List[int]) -> bool:
        n=len(nums)
        change=False
        for i in range(n-1):
            if nums[i]<=nums[i+1]:
                continue

            if change==True:
                return False

            if i==0 or nums[i-1]<=nums[i+1]:
                nums[i]=nums[i+1]
            else:
                nums[i+1]=nums[i]
            change=True
        return True