Compilare: user.cpp: In function ‘long long int f(long long int, long long int)’: user.cpp:32:8: warning: unused variable ‘i’ [-Wunused-variable] ll i; ^ user.cpp: In function ‘int main()’: user.cpp:68:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("noname2.in", "r", stdin); ^ user.cpp:69:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("noname2.out", "w", stdout); ^ user.cpp:71:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld", &n, &k); ^ user.cpp:74:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &a[i]); ^