Compilare: main.cpp: In function 'int main()': main.cpp:36:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<elem>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | for(i=1;i<N.size();i++) | ~^~~~~~~~~ main.cpp:53:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<elem>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 53 | for(i=1;i<P.size();i++) | ~^~~~~~~~~