Compilare: main.cpp: In function 'void dfs(int)': main.cpp:39:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'void dfs2(int)': main.cpp:47:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'void dfs3(int, int, int)': main.cpp:54:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); i++) ~^~~~~~~~~~~~