Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:17:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:50:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<graph[a].size(); ++j) ^ user.cpp:31:18: warning: unused variable ‘c’ [-Wunused-variable] int i, j, a, b, c, ok = 0; ^