0152: Maximum Product Subarray

Problem Statement

Given an integer array nums, find a subarray that has the largest product, and return the 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 * 104
  • -10 <= nums[i] <= 10
  • The product of any subarray of nums is guaranteed to fit in a 32-bit integer.

Code Solution

class Solution:
    def maxProduct(self, nums):
        out = cmin = cmax = nums[0]
        
        for n in nums[1:]:
            candidates = (n, cmin * n, cmax * n)
            cmax = max(candidates)
            cmin = min(candidates)
            out = max(out, cmax)
        
        return out