/in/foo.cc: In function 'void init()':
/in/foo.cc:32:8: warning: iteration 1009 invokes undefined behavior [-Waggressive-loop-optimizations]
   pp[i]=pp[i-1]*P,pq[i]=pq[i-1]*Q;
        ^
/in/foo.cc:31:15: note: within this loop
  for(int i=1;i<=N;i++)
               ^