题解 | #子数组最大乘积# PYTHON3 动态规划O（N）

#
# 
# @param arr double浮点型一维数组 
# @return double浮点型
#
class Solution:
    def maxProduct(self , arr ):
        # write code here
        global_max = max(arr)
        neg_max = None
        pos_max = None
        for e in arr:
            a = pos_max * e if pos_max else e
            b = neg_max * e if neg_max else e

            global_max = max([a, b, global_max])
            if e == 0:
                pos_max, neg_max= None, None
            else:
                pos_max = max([a, b]) if a > 1 or b > 1 else None 
                neg_max = min([a, b]) if a < 1 or b < 1 else None 
        return global_max