Compilare: user.cpp: In function ‘int main()’: user.cpp:70:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans != sel.size()) cerr << 1/0; ^ user.cpp:70:38: warning: division by zero [-Wdiv-by-zero] if (ans != sel.size()) cerr << 1/0; ^ user.cpp:58:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rmvc.in","r",stdin); ^ user.cpp:59:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rmvc.out","w",stdout); ^ user.cpp:61:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:62:68: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= m; i++) scanf("%d%d",&E[i].first,&E[i].second); ^