Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:21:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<V[index].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:34:15: warning: unused variable ‘j’ [-Wunused-variable] int x, y, i, j; ^ user.cpp:31:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ user.cpp:32:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out","w",stdout); ^ user.cpp:36:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &N, &M); ^ user.cpp:39:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &x, &y); ^