foo.cc: In function ‘int dfs(std::unordered_map<std::__cxx11::basic_string<char>, int>&, std::vector<std::vector<int> >&, int, int)’:
foo.cc:25:11: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<std::vector<int> >::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   25 |     if(cur==data.size()) {
      |        ~~~^~~~~~~~~~~~~