/in/foo.cc: In member function 'bool SPFA::main(int)':
/in/foo.cc:61:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0; i<G[Now].size(); i++) {
                 ~^~~~~~~~~~~~~~
/in/foo.cc:68:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if(used[Next]==edges.size())return false;
          ~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc: In function 'void Astar()':
/in/foo.cc:110:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<G[Now.u].size(); i++) {
                ~^~~~~~~~~~~~~~~~