use strict;
use warnings;
use List::Util qw(max min);
use Time::HiRes qw(time);

# this builds a structure that is usually retrieved from disk.
# in this example we will use this structure again and again,
# but in the real program we obviously retrieve a fresh structure
# at each iteration

my $simulation_h = {};
for ( 1 .. 70000 ) {
	my $random_start  = int( rand(5235641) );
	my $random_length = int( rand(40000) );
	push @{ $simulation_h->{$random_start} }, $random_length;
}

my $zone_o = {
	_chromosome_length => 5235641,
	_legal_range       => [ { FROM => 100000, TO => 200000 } ]
};

my $start_time = time;
scenario();
print "total loop time: " . ( time - $start_time ) . " seconds\n";
my $temp_gene_to_legal_range;
my $gene_to;

sub scenario {
	for ( my $i = 0 ; $i < 50 ; $i++ ) {
		print "i=$i time=" . ( time - $start_time ) . " seconds\n";

		# originally there was a retreive of $simulation_h from disk here

		# iterate genes

		foreach my $gene_from ( keys %{$simulation_h} ) {
			foreach my $gene_length ( @{ $simulation_h->{$gene_from} } ) {

### inlining gene_to_legal_range 
				$gene_to =
				  ( ( $gene_from + $gene_length - 1 )
					% ( $zone_o->{_chromosome_length} ) ) + 1;

				if ( $gene_to < $gene_from ) {

					# split
					# low range first
					$temp_gene_to_legal_range = [
						{ FROM => 0, TO => $gene_to },
						{
							FROM => $gene_from,
							TO   => $zone_o->{_chromosome_length}
						}
					];
				}
				else {

					# single
					$temp_gene_to_legal_range =
					  [ { FROM => $gene_from, TO => $gene_to } ];
				}


			}
		}
	}
}