Compilare: main.cpp: In function 'bool isGood(long long int)': main.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ans.size() && i<k;i++){ ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:40:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("checkin.in","r",stdin); ^ main.cpp:41:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("checkin.out","w",stdout); ^ main.cpp:45:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lli",&n); ^ main.cpp:49:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lli %lli",&v[i].a,&v[i].b); ^ main.cpp:52:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lli %lli",&k,&p); ^