Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<L[x].size(); i++) ^ user.cpp: In function ‘void df(int)’: user.cpp:25:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<L[x].size(); i++) ^