Compilare: main.cpp: In function 'int main()': main.cpp:15:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(ll i=0;i<a.size();++i) ~^~~~~~~~~ main.cpp:21:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(ll i=0;i<b.size();++i) ~^~~~~~~~~ main.cpp:23:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i>=a.size()) ~^~~~~~~~~~ main.cpp:26:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<a.size()-1) ~^~~~~~~~~~~