Compilare: user.cpp: In function ‘int main()’: user.cpp:138:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() != sum_x) { ^ user.cpp:102:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harta.in","r",stdin); ^ user.cpp:103:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harta.out","w",stdout); ^ user.cpp:105:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:114:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^