/in/foo.cc: In function 'int main()':
/in/foo.cc:52:9: error: 'memset' was not declared in this scope
   52 |         memset(visited, 0, sizeof(visited));
      |         ^~~~~~
/in/foo.cc:3:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    2 | #include <vector>
  +++ |+#include <cstring>
    3 | using namespace std;