/in/foo.cc: In function 'int main()':
/in/foo.cc:32:12: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
         if (mainOrAux[i]>0)
            ^
/in/foo.cc:24:14: warning: iteration 500000 invokes undefined behavior [-Waggressive-loop-optimizations]
         f[i] = 0;
         ~~~~~^~~
/in/foo.cc:23:15: note: within this loop
     for (i=0;i<=500000;i++)
              ~^~~~~~~~