/in/foo.cc: In function 'int main()':
/in/foo.cc:22:13: warning: iteration 100009 invokes undefined behavior [-Waggressive-loop-optimizations]
         f[i]=i;
         ~~~~^~
/in/foo.cc:21:18: note: within this loop
     for(int i=1;i<=N;i++)
                 ~^~~