List::Compare & reconciling multiple lists

#!/usr/bin/perl

use strict;
use warnings;

use List::Compare;

my (%have, 
    @seen, 
    %is_unique);

my @sets = (
  [qw( a c f g e h i )],      # X
  [qw( a b c d e f g h i )],  # Y
  [qw( a c d e f g h i )],    # Z
);

my $lcm = List::Compare->new(@sets);

foreach my $set (@sets) {
    my %seen = map { $_ => 1 } @$set;
    push @seen, \%seen;
}

foreach ($lcm->get_intersection) { 
    $have{$_} = [ 0..$#sets ];
}

my %index = map { $_ => undef } 0..$#sets;

foreach my $i (0..$#sets) {
    foreach my $elem ($lcm->get_unique($i)) {
        my @list;    
        foreach (keys %index) { $list[$_] = $index{$_} }
        $list[$i] = $i;
        $have{$elem} = [ @list ];
        $is_unique{$elem}++;
    }
}

foreach my $elem ($lcm->get_nonintersection) {
    next if $is_unique{$elem};
    my @list;
    foreach (keys %index) { $list[$_] = $index{$_} }
    foreach my $i (0..$#sets) { $list[$i] = $i if $seen[$i]{$elem} }
    $have{$elem} = [ @list ];
}    

foreach (sort keys %have) {
    foreach my $i (0..@{$have{$_}}) {
        print defined $have{$_}->[$i] ? "$_ " : '  ';
    }
    print "\n";
}

__OUTPUT__

a a a
  b
c c c
  d d
e e e
f f f
g g g
h h h
i i i
[download]

Determining list continuations

Update:

Try Number::Continuation (which originated thereof) instead. The "solution" below breaks for many edge-cases.

#!/usr/bin/perl

use strict;
use warnings;

my @nums = split / /, shift;

my ($have_begin, $have_inc, $not_follow_inc, $str);

for (my $i = 0; $i < @nums; $i++) {
    no warnings 'uninitialized';
    if (!$have_begin && !$not_follow_inc) {
        $str .= $nums[$i];
        $have_inc = $nums[$i];
        $have_begin = 1;
    } elsif (($nums[$i+1] - $nums[$i]) == 1) {
        $have_inc++;
    } elsif ($not_follow_inc) {
        $str .= ', ' . $nums[$i];
        $str .= ', ' if $i != $#nums;
        $not_follow_inc = 0;
    } else {
        $str .= '-'.++$have_inc;
        $have_begin = 0;
        $not_follow_inc = 1;
    }
}

print "$str\n";

__INPUT__

1 2 3 5 7 8 9

__OUTPUT__

1-3, 5, 7-9
[download]