/in/foo.cc: In function 'void tarjan(int)':
/in/foo.cc:17:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(re i=0;i<g[now].size();++i){
                ~^~~~~~~~~~~~~~
/in/foo.cc: In function 'void work()':
/in/foo.cc:47:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(re j=0;j<g[i].size();++j)
                    ~^~~~~~~~~~~~
/in/foo.cc:55:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(re i=0;i<q[f].size();++i)printf("%d ",q[f][i]);
                ~^~~~~~~~~~~~