#! perl -slw
use strict;
use Data::Dumper;

my @ranges = ( [17,19], [34,39], [26,29], [53,57], [43,47], [58,59]
             , [40,45], [30,33], [20,24], [10,15], [6,9],   [1,4],
             , [35,45], [7, 15],

);

#! initialise a string  of null as long as the string the ranges pertain to.
my $coal = "\0" x 100;

#! fill all the ranges with 1's
substr($coal, $_->[0], $_->[1] - $_->[0] + 1) = 1 x ($_->[1] - $_->[0] + 1) for @ranges;

#print $coal;

#! Build the new AoA of ranges by scanning the string recording starts and length of string of 1's
my (@new, $start);
for (0 .. length $coal) {
	my $c = substr($coal, $_, 1);
	next if not $start and $c ne '1';
	$start = $_ if $c eq '1' and not $start;
	next if $start and $c eq '1';
	push @new, [$start, $_-1];
	$start = undef;
}

print Dumper \@new;
__END__
$VAR1 = [
          [
            1,
            '4'
          ],
          [
            6,
            '15'
          ],
          [
            17,
            '24'
          ],
          [
            26,
            '47'
          ],
          [
            53,
            '59'
          ]
        ];