foo.cc: In function 'void deal(int, int)':
foo.cc:33:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<a.size();j++)
              ~^~~~~~~~~
foo.cc: At global scope:
foo.cc:42:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。