foo.cc: In function 'int main()':
foo.cc:32:30: warning: unused variable 'j' [-Wunused-variable]
  int Max=0,num=1,xhi,n,sum=0,j;
                              ^
foo.cc:34:13: warning: iteration 123458u invokes undefined behavior [-Waggressive-loop-optimizations]
   if(!mark[i]){
             ^
foo.cc:33:24: note: containing loop
  for(register int i=2;i<=size;i++){
                        ^

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

{"receive":"2020-04-03T02:07:02.801Z","handle":"2020-04-03T02:07:02.801Z","cache_start":"2020-04-03T02:07:02.808Z","read_cases":"2020-04-03T02:07:03.405Z","judge":"2020-04-03T02:07:03.406Z","done":"2020-04-03T02:07:05.258Z"}