Compilare: user.cpp: In function ‘int main()’: user.cpp:45:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=k;i++) ^ user.cpp:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v.size();j++) ^ user.cpp:60:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<v.size() && v[j].first==tmp) ^ user.cpp:66:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<v.size() && v[j].second) ^ user.cpp:74:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=k;i++) ^ user.cpp:31:9: warning: unused variable ‘n’ [-Wunused-variable] ULL n=next_number(); ^