Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:20:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (u = 0; u < graf[v].size(); u++) { ~~^~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:32:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^