Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:19:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < v[x].size(); ++i) ^ user.cpp:26:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < v[x].size(); ++j) { ^ user.cpp: In function ‘int main()’: user.cpp:38:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:41:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^