Maximum product difference between two pairs

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::max_product_difference(vec![5, 6, 2, 7, 4]);
    let expected = 34;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::max_product_difference(vec![4, 2, 5, 9, 7, 4, 8]);
    let expected = 64;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::max_product_difference(vec![1, 1, 1, 1]);
    let expected = 0;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::max_product_difference(vec![1, 2, 3, 4]);
    let expected = 10;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::max_product_difference(vec![10, 10, 1, 1]);
    let expected = 99;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}