/in/foo.cc: In function 'void find(int)':
/in/foo.cc:38:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=0;j<map[bg].size();j++)
                 ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'int spfa(int)':
/in/foo.cc:70:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=0;j<map[bg].size();j++)
                 ~^~~~~~~~~~~~~~~