/in/foo.cc: In function 'int expandAroundCenter(std::__cxx11::string, int, int)':
/in/foo.cc:8:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (L >= 0 && R < s.length() && s[L] == s[R]) {
                        ^
/in/foo.cc: In function 'int longestPalindrome(std::__cxx11::string)':
/in/foo.cc:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.length(); i++) {
                       ^