/in/foo.cc: In function 'int main()':
/in/foo.cc:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i=0;i<g[1].size();i++) q.push(edge(g[1][i].to,g[1][i].val));
              ~^~~~~~~~~~~~
/in/foo.cc:37:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i=0;i<g[pos].size();i++) q.push(edge(g[pos][i].to,g[pos][i].val));
                  ~^~~~~~~~~~~~~~