Longest palindromic subsequence

#[test]
fn t1() {
    let s = std::time::Instant::now();
    let v = Solution::longest_palindrome_subseq("bbbab".to_string());
    log_result!(v == 4, "t1", s, 4, v);
    assert_eq!(v, 4);
}

#[test]
fn t2() {
    let s = std::time::Instant::now();
    let v = Solution::longest_palindrome_subseq("cbbd".to_string());
    log_result!(v == 2, "t2", s, 2, v);
    assert_eq!(v, 2);
}

#[test]
fn t3() {
    // Single char
    let s = std::time::Instant::now();
    let v = Solution::longest_palindrome_subseq("a".to_string());
    log_result!(v == 1, "t3", s, 1, v);
    assert_eq!(v, 1);
}

#[test]
fn t4() {
    // Palindrome itself
    let s = std::time::Instant::now();
    let v = Solution::longest_palindrome_subseq("racecar".to_string());
    log_result!(v == 7, "t4", s, 7, v);
    assert_eq!(v, 7);
}

#[test]
fn t5() {
    // "abcba" => 5
    let s = std::time::Instant::now();
    let v = Solution::longest_palindrome_subseq("abcba".to_string());
    log_result!(v == 5, "t5", s, 5, v);
    assert_eq!(v, 5);
}