Compilare: main.cpp: In function 'Poly& operator*=(Poly&, Poly)': main.cpp:43:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::complex<double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | while(n < a.size() + b.size()) n <<= 1; | ~~^~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:84:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::complex<double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 84 | if(x >= P.size()) cout << "0\n"; | ~~^~~~~~~~~~~