Your right. My code, both my offered solution and my benchmark, are deficient. I'll keep my excuses and offer a revised solution, which I believe I have fully verified for compatability with the results of your original.

The code below runs the remove_item(s) subs against the test data for all possible $index values and compares the results against each other (yours and mine). It also benchmarks each for all input criteria and the results are that my new version now averages a tad under a third (32.9%) faster across all situations.

I hope you find this useful. 

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

[download]

The code for the full verification and the benchmark result (on my poor li'l 233MHz :) are below 

#! 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 <= $ind
+ex), 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 @dup
+s; },
      dpuu        => sub { @items = @i; $index=$start; remove_item @du
+ps; },
    });
}
__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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.63 usr +  0.00 sys =  0.63 CPU) @ 15
+87.30/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) @ 21
+23.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 21
+23.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+38.46/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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.66 usr +  0.00 sys =  0.66 CPU) @ 15
+12.86/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+36.66/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+79.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+79.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+62.50/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+79.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 19
+96.01/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+79.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+40.82/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 21
+23.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+36.66/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 19
+96.01/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+83.33/s (n=1000)
      dpuu: -1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+79.00/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 21
+23.14/s (n=1000)
      dpuu:  1 wallclock secs ( 0.66 usr +  0.00 sys =  0.66 CPU) @ 15
+12.86/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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+36.66/s (n=1000)
      dpuu:  0 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 20
+79.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+83.33/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+62.50/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) @ 19
+96.01/s (n=1000)
      dpuu:  0 wallclock secs ( 0.65 usr +  0.00 sys =  0.65 CPU) @ 15
+36.10/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) @ 20
+79.00/s (n=1000)
      dpuu:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 15
+60.06/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) @ 21
+23.14/s (n=1000)
      dpuu:  0 wallclock secs ( 0.62 usr +  0.00 sys =  0.62 CPU) @ 16
+12.90/s (n=1000)
            Rate      dpuu BrowserUk
dpuu      1613/s        --      -24%
BrowserUk 2123/s       32%        --

C:\test>

[download]
Well It's better than the Abottoire, but Yorkshire!

In reply to Re: Re: Re: round-robin on varying sequence by BrowserUk
in thread round-robin on varying sequence by dpuu

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