/in/foo.cc: In function 'bool BFS()':
/in/foo.cc:17:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=1;i<=q.size();i++){
                ~^~~~~~~~~~
/in/foo.cc:35:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<s[p].size();i++){
               ~^~~~~~~~~~~~