foo.cc: In function 'void strtobig(std::__cxx11::string, bignum&)':
foo.cc:9:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.length();i++){
              ~^~~~~~~~~~~
foo.cc: In function 'void Mul2(bignum, bignum, bignum&)':
foo.cc:21:10: warning: unused variable 'len' [-Wunused-variable]
  int i,j,len=0;
          ^~~

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

{"receive":"2020-07-23T12:01:49.065Z","handle":"2020-07-23T12:01:49.065Z","cache_start":"2020-07-23T12:01:49.072Z","read_cases":"2020-07-23T12:01:49.251Z","judge":"2020-07-23T12:01:49.255Z","done":"2020-07-23T12:01:50.421Z"}