I think we're both (partly) wrong. Actually the subject seems to support your interpretation. OTOH I'm convinced that part of the code supports mine. Actually I didn't notice the idx thing and on a better reading I think that what he wants may be along the lines of

my %seen;
for (0..$#name1) {
    next if $seen{ $name1[$_] }++;
    print $name2[$_];
}
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But unless I'm mistaking something obvious your code won't work as you're populating %seen with

( 0 => 1, ..., $#name1 => 1 )
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.