Compilare: user.cpp: In function ‘void visit(int)’: user.cpp:30:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[u].v.size(); i++) ^ user.cpp: In function ‘void as(int, int)’: user.cpp:43:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[u].v.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:80:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<l.size(); i++) ^