message: Update longest-palindromic-subsequence.cpp
diff: class Solution {
  public:
  int longestPalindromeSubseq(string s) {
  + if (s == string(s.rbegin(), s.rend())) { // optional, to optimize special case
  + return s.length();
  + }
  +
  vector<vector<int>> dp(2, vector<int>(s.size(), 1));
  for (int i = s.length() - 2; i >= 0; --i) {
  for (int j = i + 1; j < s.length(); ++j) {
  