Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:21:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[x].size(); ++ i) ^ user.cpp:33:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[x].size(); ++ i) ^ user.cpp:20:9: warning: unused variable ‘i’ [-Wunused-variable] int i, ok = 0, nod; ^ user.cpp: In function ‘void read()’: user.cpp:43:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:48:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &x, &y, &d, &c); ^