Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < ad[nod].size() ; i++ ) ^ user.cpp: In function ‘int main()’: user.cpp:22:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in","r",stdin); ^ user.cpp:23:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out","w",stdout); ^ user.cpp:25:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:28:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^