Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:24:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:113:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<G[x].size();++j) ^ user.cpp:125:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<G[x].size(); ++j) ^ user.cpp:140:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<G[x].size(); ++j) ^ user.cpp:152:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<ans.size(); ++i) ^