Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:20:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:67:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < sol[i].size(); ++j) ^ user.cpp:47:32: 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:48:34: 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:49:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:52:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^