Leetcode 152. Maximum Product Subarray

Given an integer array nums, find the contiguous subarray within an array (containing at least one number) which has the largest product.

Example 1:

Input: [2,3,-2,4]
Output: 6
Explanation: [2,3] has the largest product 6.

Example 2:

Input: [-2,0,-1]
Output: 0
Explanation: The result cannot be 2, because [-2,-1] is not a subarray.

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关键问题是负数和0怎么处理，参考最大子段和的思路，能影响以i结尾的结果无非是之前负最小和正最大。。。

import sys
class Solution:
    def maxProduct(self, nums: List[int]) -> int:
        mi,ma,res = 1,1,-sys.maxsize
        for num in nums:
            if (num<0):
                mi,ma=ma,mi
            ma = max(ma*num, num)
            mi = min(mi*num, num)
            res = max(ma,res)
        return res