Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<g[nod].size();++k) ^ user.cpp: In function ‘void dfs_t(int)’: user.cpp:25:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<t[nod].size();++k) ^ user.cpp: In function ‘int main()’: user.cpp:58:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();++j) ^ user.cpp:30:32: 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);freopen("ctc.out","w",stdout); ^ user.cpp:30:62: 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);freopen("ctc.out","w",stdout); ^ user.cpp:32:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:36:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^