Compilare: main.cpp: In function 'int main()': main.cpp:33:50: warning: narrowing conversion of '((& poz.std::map<_Key, _Tp, _Compare, _Alloc>::operator[]<int, std::vector<elem>, std::less<int>, std::allocator<std::pair<const int, std::vector<elem> > > >(prod))->std::vector<_Tp, _Alloc>::size<elem, std::allocator<elem> >() + 1ul)' from 'std::vector<elem>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] poz[prod].push_back({x, poz[prod].size() + 1}); ~~~~~~~~~~~~~~~~~^~~ main.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(poz[c].size() < p) ~~~~~~~~~~~~~~^~~