/in/foo.cc: In function 'void spfa()':
/in/foo.cc:36:5: warning: statement has no effect [-Wunused-value]
  k[1];
  ~~~^
/in/foo.cc:42:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<map[d].size();i++){
               ~^~~~~~~~~~~~~~