Compilare: user.cpp: In function ‘int pinex(int, int)’: user.cpp:22:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i+ans<divs[p].size() && divs[p][i+ans]<=lim) ^ user.cpp: In function ‘int main()’: user.cpp:48:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("farey.in", "r", stdin); ^ user.cpp:49:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("farey.out", "w", stdout); ^