Compilare: user.cpp: In function ‘int main()’: user.cpp:38:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; k && i<va.size() && vb[i]>va[i]; ++i, --k) { ^ user.cpp:42:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<va.size(); ++i) ^ user.cpp:12:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kbetray.in","r",stdin); ^ user.cpp:13:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kbetray.out","w",stdout); ^ user.cpp:18:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:20:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a.first); ^ user.cpp:21:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&b.first); ^