Compilare: main.cpp: In function 'bool check(int, const std::vector<std::__cxx11::basic_string<char> >&)': main.cpp:18:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for (int k = 0; k < s.size(); ++k) { | ~~^~~~~~~~~~ main.cpp:19:33: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'const int' [-Wsign-compare] 19 | if (s[k].size() < len) { | ~~~~~~~~~~~~^~~~~ main.cpp:25:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for (int i = 0; i < s[k].size(); ++i) { | ~~^~~~~~~~~~~~~ main.cpp:23:21: warning: unused variable 'mask' [-Wunused-variable] 23 | ull mask = (1ULL << len) - 1, h = 0; | ^~~~