#!/usr/bin/env perl -l

use strict;
use warnings;

use List::Util qw{first};

my $min = 3;
my @records = reverse(0 .. 10, 13, 17, 42);
print "All records:  @records";
my %deleted;

for my $i (0 .. $#records) {
    my $top_index = first { ! $deleted{$_} } $i .. $#records;
    last unless defined $top_index;
    my $top = $records[$top_index];
    my @group = ($top);

    for ($top_index + 1 .. $#records) {
        next if $deleted{$_};

        if (compare_sub($top, $records[$_]) <= $min) {
            push @group, $records[$_];
            ++$deleted{$_};
        }
        else {
            last;
        }
    }

    ++$deleted{$top_index};
    print "Group:        @group";
}

sub compare_sub {
    my ($x, $y) = @_;
    return abs($x - $y);
}

##</code><code>##

All records:  42 17 13 10 9 8 7 6 5 4 3 2 1 0
Group:        42
Group:        17
Group:        13 10
Group:        9 8 7 6
Group:        5 4 3 2
Group:        1 0