> ## Documentation Index
> Fetch the complete documentation index at: https://leetcode-py.wisl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> leetcode-py is a Python LeetCode practice environment generator with one CLI: lcpy. It is not a service or platform.
> Each problem is a directory under leetcode/ with README.md, solution.py, test_solution.py, helpers.py, and playground.ipynb. lcpy gen creates them from JSON templates bundled with the package.
> Examples are backed by tests; copy them verbatim.

# Maximum Product Subarray Python Solution

> Tested Python solution for LeetCode 152 with 15 pytest cases. Generate a practice environment with lcpy.

LeetCode 152, Medium. Topics: Array, Dynamic Programming. [View on LeetCode](https://leetcode.com/problems/maximum-product-subarray/description/).

Generate this problem as a practice environment: tested reference solution, 15 [parametrized pytest cases](/practice/testing), and a playground notebook:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
lcpy gen -n 152   # by problem number
lcpy gen -s maximum_product_subarray   # by problem name
```

## Problem

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.

### Examples

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

```
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 * 10^4`
* `-10 <= nums[i] <= 10`
* The product of any subarray of `nums` is **guaranteed** to fit in a **32-bit** integer.

## Solution

Reference implementation from [solution.py on GitHub](https://github.com/wislertt/leetcode-py/blob/main/leetcode/maximum_product_subarray/solution.py), full suite in [test\_solution.py](https://github.com/wislertt/leetcode-py/blob/main/leetcode/maximum_product_subarray/test_solution.py):

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
class Solution:
    # Time: O(n)
    # Space: O(1)
    def max_product(self, nums: list[int]) -> int:
        max_prod = min_prod = result = nums[0]

        for num in nums[1:]:
            if num < 0:
                max_prod, min_prod = min_prod, max_prod

            max_prod = max(num, max_prod * num)
            min_prod = min(num, min_prod * num)
            result = max(result, max_prod)

        return result
```

## Complexity

| Time | Space |
| ---- | ----- |
| O(n) | O(1)  |

## Tags

[Grind](/catalog/grind), [Blind 75](/catalog/blind-75), [NeetCode 150](/catalog/neetcode-150), [NeetCode 250](/catalog/neetcode-250), [NeetCode All](/catalog/neetcode).