/in/foo.cc: In function 'int main()':
/in/foo.cc:37:16: warning: unused variable 'y' [-Wunused-variable]
         int x, y, z;
                ^
/in/foo.cc:37:19: warning: unused variable 'z' [-Wunused-variable]
         int x, y, z;
                   ^
/in/foo.cc:56:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i=0; i<nodes.size(); i++)
                  ~^~~~~~~~~~~~~
/in/foo.cc:61:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(j=0; j<G[nodes[i]].size(); j++)
                      ~^~~~~~~~~~~~~~~~~~~
/in/foo.cc:87:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i=0; i<nodes.size(); i++)
                  ~^~~~~~~~~~~~~
/in/foo.cc:21:15: warning: unused variable 'k' [-Wunused-variable]
     int i, j, k;
               ^