foo.cc: In function 'int main()':
foo.cc:27:10: warning: iteration 1000001 invokes undefined behavior [-Waggressive-loop-optimizations]
    if(d[j]!=0) ans++;
       ~~~^
foo.cc:26:16: note: within this loop
   for(int j=0;j<=1000001;j++)
               ~^~~~~~~~~

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