Compilare: user.cpp: In function ‘void label(std::vector<std::pair<int, int> >&)’: user.cpp:10:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<_sequence.size();i++){ ~^~~~~~~~~~~~~~~~~ user.cpp:9:6: warning: unused variable ‘i’ [-Wunused-variable] int i = 0; ^ user.cpp: In function ‘bool degreeToGraph(std::vector<std::pair<int, int> >, std::__cxx11::list<std::pair<int, int> >&)’: user.cpp:22:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < _sequence.size(); i++) { ~~^~~~~~~~~~~~~~~~~~ user.cpp:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (c.first > _sequence.size() - i - 1) return false; ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:45:12: warning: unused variable ‘b’ [-Wunused-variable] int n, a, b; ^