leetcode刷题(python)－－665. Non-decreasing Array

Given an array with n integers, your task is to check if it could become non-decreasing by modifying at most 1 element.

We define an array is non-decreasing if array[i] <= array[i + 1] holds for every i (1 <= i < n).

Example 1:

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

Example 2:

Input: [4,2,1]
Output: False
Explanation: You can't get a non-decreasing array by modify at most one element.

Note: The n belongs to [1, 10,000].

class Solution:
    def checkPossibility(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        count = 0
        result = []
        if len(nums) == 1:
            return True
        else:
            for j in range(1, len(nums)):
                if nums[j] < nums[j-1]:
                    count += 1
                    result.append(j)
            if count == 0:
                return True
            elif count > 1:
                return False
            else: # count ==1
                i = result[0]
                print(nums[i])
                if i == 1 or i == len(nums) -1:
                    return True
                elif nums[i+1] >= nums[i-1]: 
                    return True
                elif nums[i-2] <= nums[i]:
                    print(nums[i-2])
                    return True
                else:
                    return False

add another answer:

class Solution:
    def checkPossibility(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        a,b=nums[:],nums[:]
        if len(nums)>2:
            for i in range(1,len(nums)-1):
                if a[i]>a[i+1]:
                    del a[i]aa
                    del b[i+1]
                    return ((a == sorted(a)) or (b==sorted(b)))
            return True
        else:
            return True