Compilare: main.cpp: In member function 'void Graph::_leveled_dfs(const int&, std::vector<int>&, std::vector<int>&, std::vector<int>&, std::stack<Edge>&, std::vector<std::vector<int> >&)': main.cpp:197:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 197 | if ( parent.size() != _nr_vertex + 1 && level.size() != _nr_vertex + 1 && return_level.size() != _nr_vertex + 1 ) | ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~ main.cpp:197:58: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 197 | if ( parent.size() != _nr_vertex + 1 && level.size() != _nr_vertex + 1 && return_level.size() != _nr_vertex + 1 ) | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~ main.cpp:197:100: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 197 | if ( parent.size() != _nr_vertex + 1 && level.size() != _nr_vertex + 1 && return_level.size() != _nr_vertex + 1 ) | ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~ main.cpp: In member function 'std::vector<int> Graph::solveTopo(std::ifstream&)': main.cpp:302:21: warning: passing NULL to non-pointer argument 2 of 'void Graph::_dfs(const int&, const int&, std::vector<int>&, std::stack<int>&)' [-Wconversion-null] 302 | _dfs(i, NULL, components, aux); // mark the other vertex in the component | ^~~~ main.cpp:157:47: note: declared here 157 | void Graph::_dfs(const int& start, const int& marker, vector<int>& mark, stack<int>& exit_time) | ~~~~~~~~~~~^~~~~~ main.cpp: In function 'int main()': main.cpp:399:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 399 | for (int e_idx = 0; e_idx < sol.second[i].size(); ++e_idx) | ~~~~~~^~~~~~~~~~~~~~~~~~~~~~