Compilare: user.cpp: In function ‘int main()’: user.cpp:79:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() < n) ^ user.cpp:49:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in","r",stdin); ^ user.cpp:50:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out","w",stdout); ^ user.cpp:52:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:56:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &part_one, &part_two); ^