/in/foo.cc: In function 'int main()':
/in/foo.cc:24:31: warning: iteration 16 invokes undefined behavior [-Waggressive-loop-optimizations]
  for(int i=0;i<=16;++i) bit[i]=1<<i;
                         ~~~~~~^~~~~
/in/foo.cc:24:15: note: within this loop
  for(int i=0;i<=16;++i) bit[i]=1<<i;
              ~^~~~