/in/foo.cc: In function 'int check_new(std::string&, int, int)':
/in/foo.cc:15:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |                 if(j_end>=s.size())continue;
      |                    ~~~~~^~~~~~~~~~