Compilare: main.cpp: In function 'void backtrack(int, int, int, std::vector<std::vector<int> >&, std::vector<int>&)': main.cpp:7:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 7 | if(current.size()==k){ | ~~~~~~~~~~~~~~^~~ main.cpp: In function 'void combinations(int)': main.cpp:22:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | for(int i=0;i<result.size();i++){ | ~^~~~~~~~~~~~~~ main.cpp:23:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 23 | for(int j=0;j<result[i].size();j++) | ~^~~~~~~~~~~~~~~~~