Compilare: main.cpp: In function 'void prel()': main.cpp:26:24: warning: iteration 1002 invokes undefined behavior [-Waggressive-loop-optimizations] used[i][j] = (1LL * used[i][j - 1] * i) % MOD; ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:24:27: note: within this loop for( int j = 1 ;j <= N; j++) ~~^~~~ main.cpp:17:18: warning: iteration 1003 invokes undefined behavior [-Waggressive-loop-optimizations] dp[i][0] = 1; ~~~~~~~~~^~~ main.cpp:15:24: note: within this loop for( int i = 0 ;i <=N ;i ++) ~~^~~