Challenge 1 for Greplin Challenge

challenge1.php

<?php

$text = strtolower('FourscoreandsevenyearsagoourfaathersbroughtforthonthiscontainentanewnationconceivedinzLibertyanddedicatedtothepropositionthatallmenarecreatedequalNowweareengagedinagreahtcivilwartestingwhetherthatnaptionoranynartionsoconceivedandsodedicatedcanlongendureWeareqmetonagreatbattlefiemldoftzhatwarWehavecometodedicpateaportionofthatfieldasafinalrestingplaceforthosewhoheregavetheirlivesthatthatnationmightliveItisaltogetherfangandproperthatweshoulddothisButinalargersensewecannotdedicatewecannotconsecratewecannothallowthisgroundThebravelmenlivinganddeadwhostruggledherehaveconsecrateditfaraboveourpoorponwertoaddordetractTgheworldadswfilllittlenotlenorlongrememberwhatwesayherebutitcanneverforgetwhattheydidhereItisforusthelivingrathertobededicatedheretotheulnfinishedworkwhichtheywhofoughtherehavethusfarsonoblyadvancedItisratherforustobeherededicatedtothegreattdafskremainingbeforeusthatfromthesehonoreddeadwetakeincreaseddevotiontothatcauseforwhichtheygavethelastpfullmeasureofdevotionthatweherehighlyresolvethatthesedeadshallnothavediedinvainthatthisnationunsderGodshallhaveanewbirthoffreedomandthatgovernmentofthepeoplebythepeopleforthepeopleshallnotperishfromtheearth');
$textLength = strlen($text);

$maxPalindromeLength = 0;
$currentWinner = '';

for ($i=0; $i<$textLength; $i++) {
	for ($j=$textLength; $j>0; $j--) {
		
		$subString = substr($text, $i, $j);
		
		if ($subString == strrev($subString)) {
			
			if (strlen($subString) > $maxPalindromeLength) {
				$maxPalindromeLength = strlen($subString); 
				$currentWinner = $subString;
			}
		}
	}
}

echo 'Password is ' . $currentWinner . ' with a length of ' . $maxPalindromeLength . ". Onward! \n\n";
// 19 minutes!
?>

challenge2.php

<?php

$x = 1;
$xPrev = 0;
$fibb = 0;
$floor = 217000;

function isPrime($num) {
	for ($i = 2; $i < $num; $i++) {
		if ($num % $i == 0 ) {
			return false; 
		}
	}
	return true;
}

while ($fibb < $floor) {
	$fibb = $x + $xPrev;
	$xPrev = $x;
	$x = $fibb;
}

while (!isPrime($fibb)) {
	$fibb = $x + $xPrev;
	$xPrev = $x;
	$x = $fibb;
}

echo 'The first prime fibonacci number larger than ' . $floor . ' is ' . $fibb . ".\n";

$z = $fibb + 1;
$sumOfPrimeDivisors = 0;

for ($i = 2; $i < $z; $i++) {
	if ($z % $i == 0 && isPrime($i)) {
		$sumOfPrimeDivisors += $i;
	}
}

echo 'The sum of prime divisors for X + 1 is ' . $sumOfPrimeDivisors . ". Onward!\n";
// 35 minutes!
?>

challenge3.php

<?php

//$set = array(1,2,3,4,6);
$set = array(3, 4, 9, 14, 15, 19, 28, 37, 47, 50, 54, 56, 59, 61, 70, 73, 78, 81, 92, 95, 97, 99);
$top = pow(2,count($set));
$arraySub = array();

for ($i=0; $i<$top; $i++) {

	$mask = str_split(sprintf('%0' . count($set) . 's', decbin($i)));
	$sum = 0;
	$subsetArray = array();
	$keyString = '';

	foreach ($mask as $key => $index) {
		if ($index == 1) {
			$sum += $set[$key];
			$subsetArray[$key] = $set[$key];
			$keyString .= $set[$key] . ':';
		}
	}

	if (in_array($sum, $set) && count($subsetArray) > 1) {
		$arraySub[$keyString] = $sum;
	}
}
echo 'The number of subsets is ' . count($arraySub). ". Score!\n";
// 60 minutes!  Needed a mad-rush tutorial on power sets!
?>