/in/foo.cc: In function 'void DFS(int)':
/in/foo.cc:11:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int k=0;k<gr[i].size();k++){
              ~^~~~~~~~~~~~~
/in/foo.cc: In function 'int BFS(int)':
/in/foo.cc:26:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int k=0;k<g[i].size();k++){
               ~^~~~~~~~~~~~
/in/foo.cc:29:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int x=0;x<g[j].size();x++){
                ~^~~~~~~~~~~~