leetcode1243

class Solution:
    def transformArray(self, arr: 'List[int]') -> 'List[int]':
        n = len(arr)
        if n < 3:
            return arr
        else:
            arr2 = arr[:]
            tag = True
            while tag:
                i = 1
                tag = False
                while i < n-1:
                    if arr[i] > arr[i-1] and arr[i] > arr[i+1]:
                        arr2[i] = arr[i] - 1
                        tag = True
                    elif arr[i] < arr[i-1] and arr[i] < arr[i+1]:
                        arr2[i] = arr[i] + 1
                        tag = True
                    i += 1
                arr = arr2[:]
            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。