Largest positive integer that exists with its negative

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::find_max_k(vec![-1, 2, -3, 3]);
    let expected = 3;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::find_max_k(vec![-1, 10, 6, 7, -7, 1]);
    let expected = 7;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::find_max_k(vec![-10, 8, 6, 7, -2, -3]);
    let expected = -1;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

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

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::find_max_k(vec![5, 3, -5, -3, 2]);
    let expected = 5;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}