The product difference between two pairs `(a, b)` and `(c, d)` is defined as `(a * b) - (c * d)`.

- For example, the product difference between `(5, 6)` and `(2, 7)` is `(5 * 6) - (2 * 7) = 16`.

Given an integer array `nums`, choose four distinct indices `w`, `x`, `y`, and `z` such that the product difference between pairs `(nums[w], nums[x])` and `(nums[y], nums[z])` is maximized.

Return the maximum such product difference.

Example 1:

    Input: nums = [5,6,2,7,4]

    Output: 34

    Explanation: We can choose indices 1 and 3 for the first pair (6, 7) and indices 2 and 4 for the second pair (2, 4).

    The product difference is (6 * 7) - (2 * 4) = 34.

Example 2:

    Input: nums = [4,2,5,9,7,4,8]

    Output: 64

    Explanation: We can choose indices 3 and 6 for the first pair (9, 8) and indices 1 and 5 for the second pair (2, 4).

    The product difference is (9 * 8) - (2 * 4) = 64.

Constraints:

- `4 <= nums.length <= 104`
- `1 <= nums[i] <= 104`