sub remove_items {
	my ($i, %del) = (0);
	@del{@_} = undef;
	@items = grep { !exists $del{$_} 
                      and ++$i 
                      or $index -= ($i <= $index), 0 
               } @items;
}

##</code><code>##

#! perl -sw
use strict;
use Benchmark;

my @i = qw( a b c x d e f a g h i j k l z m n o p q r t s t b u v w x y z );
my @dups = qw( x a z t b );
my $index;
my @items = @i;

sub remove_item {
  my %del = map { $_ => 1 } @_;

  my @part_1 = grep { !exists $del{$_} } @items[0..$index];
  my @part_2 = grep { !exists $del{$_} } @items[$index+1..$#items];

  $index = $#part_1;
  @items = (@part_1, @part_2);
}

sub remove_items {
	my ($i, %del) = (0);
	@del{@_} = undef;
	@items = grep { !exists $del{$_} and ++$i or $index -= ($i <= $index), 0 } @items;
}
for my $start ( 0..$#items ) {
	@items = @i; $index=$start;
	remove_item @dups;
	my $dpuuResults = "$index:$items[$index]:@items\n";
	@items = @i; $index=$start;
	remove_items @dups;
	my $BUKResults = "$index:$items[$index]:@items\n";

	print "Mismatch: dpuu gave:\n$dpuuResults\nBUK gave: $BUKResults\n" if $dpuuResults ne $BUKResults;

	Benchmark::cmpthese( 1000, {
	  BrowserUk => sub { @items = @i; $index=$start; remove_items @dups; },
	  dpuu		=> sub { @items = @i; $index=$start; remove_item @dups; },
	});
}
__DATA__
C:\test>195796 30
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.63 usr +  0.00 sys =  0.63 CPU) @ 1587.30/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1587/s        --      -24%
BrowserUk 2083/s       31%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.47 usr +  0.00 sys =  0.47 CPU) @ 2123.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -28%
BrowserUk 2123/s       38%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.47 usr +  0.00 sys =  0.47 CPU) @ 2123.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -28%
BrowserUk 2123/s       38%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1538.46/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1538/s        --      -24%
BrowserUk 2037/s       32%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.66 usr +  0.00 sys =  0.66 CPU) @ 1512.86/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1513/s        --      -27%
BrowserUk 2083/s       38%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -25%
BrowserUk 2037/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -25%
BrowserUk 2037/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2083/s       36%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -25%
BrowserUk 2037/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2079/s       35%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1562.50/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1562/s        --      -25%
BrowserUk 2079/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -23%
BrowserUk 2037/s       31%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2079/s       35%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.50 usr +  0.00 sys =  0.50 CPU) @ 1996.01/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -22%
BrowserUk 1996/s       28%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -25%
BrowserUk 2083/s       34%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -23%
BrowserUk 2037/s       31%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -25%
BrowserUk 2079/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2040.82/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -24%
BrowserUk 2041/s       31%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.47 usr +  0.00 sys =  0.47 CPU) @ 2123.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -28%
BrowserUk 2123/s       38%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -25%
BrowserUk 2037/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.50 usr +  0.00 sys =  0.50 CPU) @ 1996.01/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -22%
BrowserUk 1996/s       28%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu: -1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -25%
BrowserUk 2083/s       34%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2079/s       35%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.47 usr +  0.00 sys =  0.47 CPU) @ 2123.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.66 usr +  0.00 sys =  0.66 CPU) @ 1512.86/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1513/s        --      -29%
BrowserUk 2123/s       40%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2083/s       36%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.49 usr +  0.00 sys =  0.49 CPU) @ 2036.66/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -23%
BrowserUk 2037/s       31%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -26%
BrowserUk 2079/s       35%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2083.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1562.50/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1562/s        --      -25%
BrowserUk 2083/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  0 wallclock secs ( 0.50 usr +  0.00 sys =  0.50 CPU) @ 1996.01/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 1536.10/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1536/s        --      -23%
BrowserUk 1996/s       30%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.48 usr +  0.00 sys =  0.48 CPU) @ 2079.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1560.06/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1560/s        --      -25%
BrowserUk 2079/s       33%        --
Benchmark: timing 1000 iterations of BrowserUk, dpuu...
 BrowserUk:  1 wallclock secs ( 0.47 usr +  0.00 sys =  0.47 CPU) @ 2123.14/s (n=1000)
      dpuu:  0 wallclock secs ( 0.62 usr +  0.00 sys =  0.62 CPU) @ 1612.90/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1613/s        --      -24%
BrowserUk 2123/s       32%        --

C:\test>