Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:28:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void dfs3(int)’: user.cpp:38:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^