Compilare: user.cpp: In function ‘void dfs2(int)’: user.cpp:13:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(!viz[*it] && v[*it].size()>=k) dfs2(*it); ^ user.cpp: In function ‘int main()’: user.cpp:77:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(v[i].size()>=k && !viz[i]) ^ user.cpp:46:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.in","r",stdin); ^ user.cpp:47:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.out","w",stdout); ^ user.cpp:48:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&k); ^ user.cpp:59:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.cpp:60:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",a[i]+1); ^