Solving Euler problems with @jakedobkin

gistfile1.pl

use strict;
#use bigint;

use constant TARGET => 20;
use constant VERBOSE => 1;

my $total = 0;
my %fib;

sub fib($)
{
	my $num = shift;
	($num<=1) and return(0);
	($num==2) and return(1);
	
	(VERBOSE > 2) and print "looking at $num...\n";
	
	if ($fib{$num} > 0) { 
		(VERBOSE > 2) and print "We already knew that the ", $num, "th number in the sequence was", $fib{$num}, "\n";
		return ($fib{$num});
	}
	
	$fib{$num} = (fib($num-1) + fib($num-2));
	
	(VERBOSE > 1) and print "Looks like the fibonacci number for $num is ", $fib{$num}, "\n";
	
	unless ($fib{$num} % 2)  { 
		$total += $fib{$num}; 
		VERBOSE and print "Current total of evens is $total after adding the ", $num, "th number in the sequence is, ", $fib{$num}, "\n";
	} 
	
	return ($fib{$num});
}

print "Current total of evens is $total\n";
print "fibonacci ", TARGET, " is ", fib(TARGET), "\n";


__END__