foreach (sort { $a <=> $b } keys %hash) { push @c, \@{$hash{$_}}; }

##</code><code>##

@c = map { 
  \@{ $hash{$_} }
} (sort { $a <=> $b } keys %hash);

##</code><code>##

push @c, map { 
  \@{ $hash{$_} }
} (sort { $a <=> $b } keys %hash);