Compilare: main.cpp: In function 'int main()': main.cpp:19:23: 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] 19 | for (int i = 1; i < a.size(); i++) { | ~~^~~~~~~~~~ main.cpp:20:27: 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] 20 | for (int j = 1; j < b.size(); j++) { | ~~^~~~~~~~~~