Compilare: user.cpp: In function ‘void mycopy(long long int*, long long int*)’: user.cpp:10:24: warning: argument to ‘sizeof’ in ‘void* memset(void*, int, size_t)’ call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess] memset(a, 0, sizeof(a)); ^ user.cpp: In function ‘void add(long long int*, long long int*)’: user.cpp:43:32: warning: operation on ‘j’ may be undefined [-Wsequence-point] a[++j] = a[j] + t % MOD; ^ user.cpp: In function ‘int main()’: user.cpp:68:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gard2.in", "r", stdin); ^ user.cpp:69:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gard2.out", "w", stdout); ^ user.cpp:70:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^