Compilare: main.cpp: In function 'void solve()': main.cpp:20:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for (int i=0; i<b.size(); i++) | ~^~~~~~~~~ main.cpp:39:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 39 | for (int i=0; i<b.size(); i++) | ~^~~~~~~~~ main.cpp:42:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 42 | for (int i=0; i<c.size(); i++) | ~^~~~~~~~~ main.cpp:65:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 65 | for (int i=0; i<b.size(); i++) | ~^~~~~~~~~ main.cpp:68:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 68 | for (int i=0; i<c.size(); i++) | ~^~~~~~~~~