Compilare: user.cpp: In function ‘void DFS(int, int, int)’: user.cpp:25:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[nod].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:73:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<v[i].size(); j++) ^ user.cpp:60:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin); ^ user.cpp:61:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.out","w",stdout); ^ user.cpp:62:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:65:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^