152. Maximum Product Subarray

Given an integer array nums, find a

subarray

that has the largest product, and returnthe product.

The test cases are generated so that the answer will fit in a 32-bit integer.

Example 1:

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

Example 2:

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

Constraints:

• 1 <= nums.length <= 2 * 10<sup>4</sup>

• -10 <= nums[i] <= 10

• The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.

Solution:

class Solution:
    def maxProduct(self, nums: List[int]) -> int:
        res = nums[0]
        curMin, curMax = 1, 1

        for n in nums:
            tmp = curMax * n
            curMax = max(n * curMax, n * curMin, n)
            curMin = min(tmp, n * curMin, n)
            res = max(res, curMax)
        return res