Compilare: main.cpp: In function 'void bfs(int)': main.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < l[el].size(); i++) { ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < yes.size(); ++i) fout << yes[i] << " "; ~~^~~~~~~~~~~~