Compilare: main.cpp: In function 'int main()': main.cpp:20:26: warning: comparison of integer expressions of different signedness: 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 20 | if (s.size() >= l && s.size() <= u) { | ~~~~~~~~~^~~~ main.cpp:20:43: warning: comparison of integer expressions of different signedness: 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 20 | if (s.size() >= l && s.size() <= u) { | ~~~~~~~~~^~~~ main.cpp:23:26: warning: comparison of integer expressions of different signedness: 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 23 | if (s.size() > u) { | ~~~~~~~~~^~~