Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:27:35: 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:36:36: 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(int, char**)’: user.cpp:76:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<ctc[i].size();++j) ^ user.cpp:46:36: 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:47:38: 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:49:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:53:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^