selling_rna.cpp:28:19: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   28 | int convert(const auto& a) { return a == 'A' ? 0 : a == 'C' ? 1 : a == 'G' ? 2 : 3; }
      |                   ^~~~
selling_rna.cpp:34:17: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   34 | void mark(const auto& s) {
      |                 ^~~~
selling_rna.cpp:43:16: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   43 | void add(const auto& s, int id) {
      |                ^~~~
selling_rna.cpp:52:15: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   52 | int get(const auto& s, Hash e) {
      |               ^~~~
selling_rna.cpp: In instantiation of 'void mark(const auto:24&) [with auto:24 = std::__cxx11::basic_string<char>]':
selling_rna.cpp:77:42:   required from here
selling_rna.cpp:36:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |   for (int i = 1; i <= s.size(); ++i) {
      |                   ~~^~~~~~~~~~~
selling_rna.cpp: In instantiation of 'void add(const auto:25&, int) [with auto:25 = std::__cxx11::basic_string<char>]':
selling_rna.cpp:80:18:   required from here
selling_rna.cpp:45:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |   for (int i = 1; i <= s.size(); ++i) {
      |                   ~~^~~~~~~~~~~
selling_rna.cpp: In instantiation of 'int get(const auto:26&, Hash) [with auto:26 = std::__cxx11::basic_string<char>]':
selling_rna.cpp:83:62:   required from here
selling_rna.cpp:54:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |   for (int i = 1; i <= s.size(); ++i) {
      |                   ~~^~~~~~~~~~~