Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:20:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<fii[nod].size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:30:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("pm2.in","r",stdin); ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("pm2.out","w",stdout); ^ user.cpp:34:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^ user.cpp:37:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&v[i]); ^ user.cpp:41:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&k); ^ user.cpp:44:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&x); ^