Compilare: user.cpp: In function ‘int main()’: user.cpp:25:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ans.size();i++) ^ user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("armonica.in","r",stdin); ^ user.cpp:10:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("armonica.out","w",stdout); ^ user.cpp:14:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&b); ^