[leetcode]665. Non-decreasing Array @ python

版权声明：版权归个人所有，未经博主允许，禁止转载 https://blog.csdn.net/danspace1/article/details/88945442

原题

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].

解法

遍历nums, 如果发现nums[i] > nums[i+1], 有两种可能, 一种是将nums[i]取较小值nums[i+1], 另一种是将nums[i+1]取较大值nums[i], 然后检查这两种方法的数组是否为递增数组.

代码

class Solution(object):
    def checkPossibility(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        one, two = nums[:], nums[:]
        for i in range(len(nums)-1):
            if nums[i] > nums[i+1]:
                one[i] = nums[i+1]
                two[i+1] = nums[i]
                break
        return one == sorted(one) or two == sorted(two)