/in/foo.cc: In function 'void spfa(int)':
/in/foo.cc:41:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<mymap[now.mynext].size();i++)
               ~^~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:81:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<=in.size();j=j++)
               ~^~~~~~~~~~~
/in/foo.cc:81:29: warning: operation on 'j' may be undefined [-Wsequence-point]
   for(int j=0;j<=in.size();j=j++)
                            ~^~~~
/in/foo.cc:84:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if(in[j]!=' '&&j<in.size()) k=k*10+in[j]-'0';
                   ~^~~~~~~~~~