Compilare: main.cpp: In function 'void dfs(std::vector<std::vector<int> >&, int)': main.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < adj_list[vertex].size(); i++ ) { ~~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int count_components(std::vector<std::vector<int> >&)': main.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 1; i < adj_list.size(); i++ ) { ~~^~~~~~~~~~~~~~~~~