leetcode1243

 1 class Solution:
 2     def transformArray(self, arr: 'List[int]') -> 'List[int]':
 3         n = len(arr)
 4         if n < 3:
 5             return arr
 6         else:
 7             arr2 = arr[:]
 8             tag = True
 9             while tag:
10                 i = 1
11                 tag = False
12                 while i < n-1:
13                     if arr[i] > arr[i-1] and arr[i] > arr[i+1]:
14                         arr2[i] = arr[i] - 1
15                         tag = True
16                     elif arr[i] < arr[i-1] and arr[i] < arr[i+1]:
17                         arr2[i] = arr[i] + 1
18                         tag = True
19                     i += 1
20                 arr = arr2[:]
21             return arr

这题目描述的不是很清楚，没有说明是每次更新“即时生效”还是每次更新“批量生效”，做过题目的应该能明白我我说的意思。