Compilare: main.cpp: In function 'void bfs(int)': main.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<adj[u].size();i++) { ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:33:12: warning: unused variable 'j' [-Wunused-variable] int i, j; ^