README.md

1913. Maximum Product Difference Between Two Pairs

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

Solutions (Rust)

1. Solution

impl Solution {
    pub fn max_product_difference(nums: Vec<i32>) -> i32 {
        let mut max = (i32::MIN, i32::MIN);
        let mut min = (i32::MAX, i32::MAX);

        for num in nums {
            if num >= max.0 {
                max = (num, max.0);
            } else if num > max.1 {
                max.1 = num;
            }
            if num <= min.0 {
                min = (num, min.0)
            } else if num < min.1 {
                min.1 = num;
            }
        }

        max.0 * max.1 - min.0 * min.1
    }
}