problem 4

gistfile1.aw

<?php

function isPalindrome($number) {
	$numberLength = strlen($number);
	$isEven = $numberLength %2 == 0;
	$isPalindrome = false;

		while(true) {
			$first = substr($number, 0, 1);
			$last = substr($number, -1, 1);

			if($first != $last) break;

			$number = substr($number, 0, -1);
			$number = substr($number, 1);

			if(strlen($number) == 1 || strlen($number) == 0) {
				$isPalindrome = true;
				break;
			}
		}
		return $isPalindrome;
}

$biggestDrome = 0;

for($i = 999; $i > 99; $i--) {
	for($j = 999; $j > 99; $j --) {
		$product = $i*$j;
		if($product % 11 == 0) {
		  if(isPalindrome($product)) {
  			if($product > $biggestDrome) {
  				$biggestDrome = $product;
  			}
  		}
		}
	}
}

var_dump($biggestDrome);

?>