Compilare: main.cpp: In function 'int main()': main.cpp:31:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | if(k <= sel.size()) { | ~~^~~~~~~~~~~~~ main.cpp:33:38: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | for(idx = k - 1; idx < sel.size(); idx++) { | ~~~~^~~~~~~~~~~~