foo.cc: In function 'int main()':
foo.cc:15:23: warning: iteration 9999 invokes undefined behavior [-Waggressive-loop-optimizations]
   15 |                 if(a[i])
      |                    ~~~^
foo.cc:13:22: note: within this loop
   13 |         for(int i=1;i<=10000;i++)
      |                     ~^~~~~~~

[Hydro](https://hydro.ac)提供评测服务