foo.cc: In member function 'void ds::str::AC_automaton::insert(std::string)':
foo.cc:326:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  326 |         for (int i = 0; i < s.length(); i++) {
      |                         ~~^~~~~~~~~~~~
foo.cc: In member function 'int ds::str::AC_automaton::query(std::string)':
foo.cc:352:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  352 |         for (int i = 0; i < s.length(); i++) {
      |                         ~~^~~~~~~~~~~~
foo.cc: At global scope:
foo.cc:404:1: error: expected '}' at end of input
  404 | }
      | ^
foo.cc:74:14: note: to match this '{'
   74 | namespace ds {
      |              ^

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