#!/perl
use strict;
use warnings FATAL => qw(all);

use List::MoreUtils qw( zip );
die "Where is an array?\n" unless @ARGV;
my @array = @ARGV;
print "@array\n";
my $aa = unsort([@array]);
print "@$aa\n";

sub unsort
{
  my $aref = shift;
  my @tmp;
  my %nums;
  @tmp[0 .. $#$aref] = (undef) x $#$aref; 
  @$aref = sort {$a <=> $b} @$aref;
  @nums{@$aref} = @tmp;
  return $aref if scalar keys %nums == 1;
  my $half = int(($#$aref + 2 )/ 2 );
  
  if ( scalar keys %nums == 2 )
  {
    if ( $aref->[$half - 1] == $aref->[$#$aref]  )
    {
      @$aref = ( @$aref[$half .. $#$aref],
                 @$aref[0..$half-1] );
      @$aref[$half-1, $#$aref] = @$aref[$#$aref,$half-1];
    }
  }
  else
  {
    for my $i ( 0 .. $half - 1 )
    {
      last if $i + $half > $#$aref;
      if ( $aref->[$i] == $aref->[$i + $half-1]  )
      {
        @$aref = ( @$aref[$i .. $#$aref], @$aref[0..$i-1] );
      }
    }
  }
  my @first  = @$aref[0..$half-1];
  my @second = @$aref[$half .. $#$aref]; 
  
  #################### An ugly hack for for odd-size arrays.
    if ( scalar @$aref % 2 ) { push @second, 0; }
  
  @tmp = zip @first, @second; 
  
  if ( scalar @$aref % 2 ) { pop @tmp;}
  #################### 

  @$aref = @tmp;
  return $aref;
}