/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<lists.size(); i++)
              ~^~~~~~~~~~~~~
/in/foo.cc:30:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(j=0; j<G[node].size(); j++)
                  ~^~~~~~~~~~~~~~~
/in/foo.cc:37:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<cur.size(); i++)
              ~^~~~~~~~~~~
/in/foo.cc:41:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<cur.size(); i++)
              ~^~~~~~~~~~~
/in/foo.cc:44:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i=0; i<cur.size(); i++)
                  ~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:60:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j, k;
            ^
/in/foo.cc:60:15: warning: unused variable 'k' [-Wunused-variable]
     int i, j, k;
               ^
/in/foo.cc:78:8: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
     dfs(root, 1);
     ~~~^~~~~~~~~