use warnings;
use strict;

my @array  = qw(-20 20 1 1 2 2 2 9 3 -4 -4 5 -20 20 7 7 7);
my @array1 = qw( 10 11 7 9 3 3 3 1 3  4  5 5   1 30 8 7 8);

for( map{ my $k=$_; [ sort{ $array1[$b]<=>$array1[$a] } grep{ $k eq $array[$_] } 0..$#array ] } @array ) {
		shift @$_ if @$_==1 or $array1[$$_[0]] ne $array1[$$_[1]];
		$array[$_] = $array1[$_] = '' for @$_;
}
$"=','; print "\@output  = (@array);\n\@output1 = (@array1);\n";