#!/usr/bin/perl
use strict;
use warnings;

my @data = qw/12345.pdf
              12345_-v1.pdf  12345_Av1.pdf    
              123456_-v1.pdf 123456_Av1.pdf 123456_Bv1.pdf   
              g05495_1_-v1.pdf 
              zprt0019548_wiper_die-nc_-1.pdf zprt0019548_wiper_die-nc_-2.pdf 
              zprt0016809_fg_tooling_A2.pdf   zprt0016809_fg_tooling_A3.pdf/;
my %hash;
my @unversioned;

for my $f (sort @data) {
  my ($version,@key) = reverse split /_/,$f;
  my $key = join "_",reverse @key;
  if($key) {
    $hash{$key} = $version;
  }
  else {
    push @unversioned,$version;
  }
}

for my $key (keys %hash) {
  print $key . '_' . $hash{$key} . "\n";
}
print join "\n",@unversioned,q{};