gistfile1.aw

<?php
	$ceiling = 600851475143;
	$factor = -1;
	for ($i = 1; $i < sqrt($ceiling); $i += 2) {
		$factor = getLargestFactor($i);
		if ($factor == 1) {
			primeList($i);
		}
	}
	
	$ram = memory_get_usage(TRUE);
	$factor = getLargestFactor($ceiling);
	print "Fuck yeah! The largest prime factor of $ceiling is $factor! It only took $ram bytes of RAM.";

	function getLargestFactor($i) {
		$primes = primeList();
		rsort($primes);
		foreach($primes as $p) {
			if ($i % $p == 0) {
				return $p;
			}
		}
		return 1;
	}
	
	function primeList($i = NULL) {
		static $primes = array(2,1);
		if (isset($i)) {
			array_unshift($primes, $i);
		}
		return $primes;
	}
?>