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

use Set::IntSpan;

my $data = '43:1:1; 43:1:2; 43:1:3; 43:1:4; 43:1:5; 43:1:6; 27:3:7; 27:3:8; 27:3:9; 65:1:4; 65:1:18';

my %result;
my $out = sub {
    my $key = (keys %result)[0] or return;
    print "$key:", delete $result{$key}, ';';
};
while ($data =~ /([0-9]+:[0-9]+):([0-9]+)/g) {
    my ($key, $value) = ($1, $2);
    if (exists $result{$key}) {
        $result{$key}->U($value);

    } else {
        $out->();
        $result{$key} = 'Set::IntSpan'->new($value);
    }
}
$out->();