Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:15:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[a].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:23:15: warning: unused variable ‘x’ [-Wunused-variable] int i, a, b, x, y; ^ user.cpp:23:18: warning: unused variable ‘y’ [-Wunused-variable] int i, a, b, x, y; ^