Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:16:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[nod].size(); i++) ^ user.cpp: In function ‘void DFST(int)’: user.cpp:25:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<Gt[nod].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:58:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<ctc[i].size(); j++) ^ user.cpp:32:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in","r",stdin); ^ user.cpp:33:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out","w",stdout); ^ user.cpp:34:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:38:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^