arunhorne,
You have a prototype, which is a little different than a regular subroutine. I will leave reading about the prototype to you and how to get it to work with either arrays or references to arrays.

sub util_remove_duplicates {
    my $array_ref = shift;
    my %hash;
    @hash{@{$array_ref}} = ();
    return keys %hash;
}
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There are a couple of things to point out.

Check out wantarray to see if the sub is being called in list or scalar context - that way you can return the list or a ref

You do not need to undef the hash after you create it with my

You could reduce it even further, but it becomes less readable

Cheers - L~R

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