Compilare: main.cpp: In function 'void BT(int)': main.cpp:82:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 82 | if(i == var.size()) | ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:116:22: warning: array subscript has type 'char' [-Wchar-subscripts] 116 | notFirst[x[0]] = 1; | ^ main.cpp:117:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 117 | for(int i = 0; i < x.size(); ++i) | ~~^~~~~~~~~~ main.cpp:126:22: warning: array subscript has type 'char' [-Wchar-subscripts] 126 | notFirst[x[0]] = 1; | ^