/in/foo.cc: In function 'int SPFA(int)':
/in/foo.cc:64:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<edgenode>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |                 for (int z = 0; z < edge[x].size(); z++)
      |                                 ~~^~~~~~~~~~~~~~~~