sub shuffle($$$) {
    my ($seed, $max, $input) = @_;

    # $max > $input
    # $max > 0
    # $input >= 0

    my $result;

    # calculate $result

    # $result >= 0
    # $result < $max

    return $result
}
##</code><code>##

get_rand(\@$$) {
    my ($list, $seed, $input) = @_;
    return $list->[shuffle($seed, scalar(@$list), $input)];
}

my $list = [10, 20, 30, 40, 50, 60];

for (my $i = 0; $i < scalar(@$list); $i++) {
    print get_rand($list, 42, $i) . ' ';
}

# might print 40 10 20 60 30 50