Compilare: user.cpp: In function ‘int main()’: user.cpp:45:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < vec.size(); i++) { ^ user.cpp:38:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evantai.in","r",stdin); ^ user.cpp:39:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evantai.out","w",stdout); ^ user.cpp:41:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:42:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i = 1; i <= n; i++) scanf("%d", a + i); ^