Compilare: main.cpp: In function 'void dfs(int)': main.cpp:28:19: 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:36:19: 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:43:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:123:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[n1].size();i++) ~^~~~~~~~~~~~~