Compilare: main.cpp: In function 'int main()': main.cpp:22:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | for (i = 0; i < s.size(); i++) | ~~^~~~~~~~~~ main.cpp:28:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | for (i = 0; i < sol.size(); i += 2) | ~~^~~~~~~~~~~~ main.cpp:29:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 29 | if (i + 1 >= sol.size()) | ~~~~~~^~~~~~~~~~~~~ main.cpp:18:12: warning: unused variable 'j' [-Wunused-variable] 18 | int i, j; | ^