Given an array nums 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 nums[i] <= nums[i + 1] holds for every i (0-based) such that (0 <= i <= n - 2).
最多只能改变1个元素，问能不能让这个数组变成不递减数组。
考虑两种情况
1 2 3 5 4 6 -> 把5改成4就挺好，能保证后面的顺序
1 2 5 6 3 7 ->只能把3改成6而不是把6改成3
所以就是当第一次遇到后面的元素小于前面的时候，判断下应该是改前面的还是后面的元素，如果遇到第二次需要修改，那就返回false
class Solution(object): def checkPossibility(self, nums): """ :type nums: List[int] :rtype: bool """ modify = False for i in range(1, len(nums), 1): if nums[i] < nums[i - 1]: if modify: return False else: if i - 2 >= 0 and nums[i - 2] >= nums[i]: nums[i] = nums[i - 1] else: nums[i - 1] = nums[i] modify = True return True
原文：https://www.cnblogs.com/whatyouthink/p/13303085.html