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152. Maximum Product Subarray

Array Dynamic Programming

Problem - Maximum Product Subarray

Medium

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.

Solutions

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class Solution:
    def maxProduct(self, nums: List[int]) -> int:
        result = dp = f = nums[0]
        for num in nums[1:]:
            current_dp, current_f = dp, f
            dp = max(num, current_dp * num, current_f * num)
            f = min(num, current_dp * num, current_f * num)
            result = max(result, dp)

        return result

Submission Stats:

  • Runtime: 11 ms (50.79%)
  • Memory: 18.4 MB (53.54%)