/in/foo.cc: In function 'void BFS(int)':
/in/foo.cc:16:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int k=0;k<g[i].size();k++){
               ~^~~~~~~~~~~~
/in/foo.cc: In function 'void topo()':
/in/foo.cc:34:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<gg[u].size();i++){
               ~^~~~~~~~~~~~~
/in/foo.cc: In function 'void dp_()':
/in/foo.cc:45:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<gg[u].size();j++){
               ~^~~~~~~~~~~~~