Compilare: user.cpp: In function ‘void DFS(int, int, int, int)’: user.cpp:16:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[x].size(); ++i) ^ user.cpp:17:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[y].size(); ++j) ^ user.cpp: In function ‘int main()’: user.cpp:52:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[i].size(); ++j) ^