Compilare: main.cpp: In function 'int main()': main.cpp:41:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 41 | for(ll i = 0; i < a.size(); ++i) | ~~^~~~~~~~~~ main.cpp:56:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 56 | for(ll i = 0; i <= a.size() - 2; ++i) | ~~^~~~~~~~~~~~~~~ main.cpp:64:28: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 64 | for(ll i = a.size(); i < b.size(); ++i) | ~~^~~~~~~~~~