Compilare: main.cpp: In function 'void back(int, int, int, std::vector<int>&, int)': main.cpp:8:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 8 | if(sol.size()==k){ | ~~~~~~~~~~^~~ main.cpp:9:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 9 | for(int i=0;i<sol.size();i++){ | ~^~~~~~~~~~~