/in/foo.cc: In function 'void insertWords(std::__cxx11::string)':
/in/foo.cc:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<s.size();i++){
                 ~^~~~~~~~~
/in/foo.cc: In function 'int query(std::__cxx11::string)':
/in/foo.cc:62:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<s.size();i++){    //遍历文本串
                 ~^~~~~~~~~