/in/foo.cc: In function 'void work()':
/in/foo.cc:29:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < vc[i].size(); ++j) {
                         ~~^~~~~~~~~~~~~~
/in/foo.cc:46:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j = 0; j < node[i].size(); ++j) {
                             ~~^~~~~~~~~~~~~~~~