Compilare: main.cpp: In function 'void backtracking(std::vector<int>&)': main.cpp:28:30: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 28 | if (selectedItems.size() == n * m) { | ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~ main.cpp:54:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 54 | for (int i = 0; i < elements.size(); ++i) { | ~~^~~~~~~~~~~~~~~~~