Compilare: main.cpp: In function 'int main()': main.cpp:31:22: 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] 31 | for(int i = 0; i < s.size(); i++) | ~~^~~~~~~~~~ main.cpp:34:26: 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] 34 | for(int j = i; j < s.size(); j++) | ~~^~~~~~~~~~ main.cpp:46:26: 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] 46 | for(int j = 0; j < a.size(); j++) | ~~^~~~~~~~~~