/in/foo.cc: In function 'int main()':
/in/foo.cc:103:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      for (int j = 0; j < V[cur].size(); ++j) {
                      ~~^~~~~~~~~~~~~~~
/in/foo.cc:111:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      for (int j = 0; j < V[cur].size(); ++j) {
                      ~~^~~~~~~~~~~~~~~