Longest uncommon subsequence i

#[test]
fn t1() {
    let s = std::time::Instant::now();
    let v = Solution::find_lu_slength("aba".to_string(), "cdc".to_string());
    log_result!(v == 3, "t1", s, 3, v);
    assert_eq!(v, 3);
}

#[test]
fn t2() {
    let s = std::time::Instant::now();
    let v = Solution::find_lu_slength("aaa".to_string(), "bbb".to_string());
    log_result!(v == 3, "t2", s, 3, v);
    assert_eq!(v, 3);
}

#[test]
fn t3() {
    let s = std::time::Instant::now();
    let v = Solution::find_lu_slength("aaa".to_string(), "aaa".to_string());
    log_result!(v == -1, "t3", s, -1, v);
    assert_eq!(v, -1);
}

#[test]
fn t4() {
    let s = std::time::Instant::now();
    let v = Solution::find_lu_slength("a".to_string(), "b".to_string());
    log_result!(v == 1, "t4", s, 1, v);
    assert_eq!(v, 1);
}

#[test]
fn t5() {
    // Different length strings
    let s = std::time::Instant::now();
    let v = Solution::find_lu_slength("ab".to_string(), "abc".to_string());
    log_result!(v == 3, "t5", s, 3, v);
    assert_eq!(v, 3);
}