/in/foo.cc: In function 'void dfs(int, int*)':
/in/foo.cc:64:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     for (int i = 1; i < op.size(); i ++ ) {
      |                     ~~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:87:5: error: 'memset' was not declared in this scope
   87 |     memset(f, false, sizeof(f));
      |     ^~~~~~
/in/foo.cc:5:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    4 | #include <vector>
  +++ |+#include <cstring>
    5 | using namespace std;