/in/foo.cc: In function 'void res()':
/in/foo.cc:13:82: warning: iteration 1000004 invokes undefined behavior [-Waggressive-loop-optimizations]
   13 |                         if ((dp[j]%1000000000)*(dp[k]%1000000000)%1000000000>dp[i])dp[i]=max(dp[i],(dp[j]%1000000000)*(dp[k]%1000000000)%1000000000);
      |                                                                              ~~~~^
/in/foo.cc:8:23: note: within this loop
    8 |         for (int i=1;i<=N;i++)
      |                      ~^~~