/in/foo.cc: In function 'void dfs(int, int, std::string)':
/in/foo.cc:13:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   13 |         if(s.length() - idx<k-cnt) return;
      |            ~~~~~~~~~~~~~~~~^~~~~~
/in/foo.cc:15:15: 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(idx==s.length())
      |            ~~~^~~~~~~~~~~~
/in/foo.cc:20:46: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   20 |                         while(path.length()-1>i&&path[i] == '0') i++;
      |                               ~~~~~~~~~~~~~~~^~