Computer Smuggler

<?php
$parts = preg_split('/,\s+/', $_GET['list'], -1, PREG_SPLIT_NO_EMPTY);
$cpParts = array_fill_keys($parts, 0);
foreach ($parts as $part) {
    $cpParts[$part] += 1;
}

$money = 0;
foreach ($cpParts as $key => $count) {
    switch ($key) {
        case 'CPU':
            $cost = 85 * $count;
            break;
        case 'RAM':
            $cost = 35 * $count;
            break;
        case 'ROM':
            $cost = 45 * $count;
            break;
        case 'VIA':
            $cost = 45 * $count;
            break;
    }
    if ($count >= 5) {
        $cost /= 2;
    }
    $money -= $cost;
}

$computers = 0;
while ($cpParts['CPU'] > 0 && $cpParts['RAM'] > 0 && $cpParts['ROM'] > 0 && $cpParts['VIA'] > 0) {
    $cpParts['CPU'] -= 1;
    $cpParts['RAM'] -= 1;
    $cpParts['ROM'] -= 1;
    $cpParts['VIA'] -= 1;
    $computers++;
    $money += 420;
}

$partsLeft = 0;
foreach ($cpParts as $key => $count) {
    switch ($key) {
        case 'CPU':
            $cost = 85 * $count;
            $partsLeft += $count;
            break;
        case 'RAM':
            $cost = 35 * $count;
            $partsLeft += $count;
            break;
        case 'ROM':
            $cost = 45 * $count;
            $partsLeft += $count;
            break;
        case 'VIA':
            $cost = 45 * $count;
            $partsLeft += $count;
            break;
    }
    $money += ($cost / 2);
}

echo '<ul>';
echo "<li>{$computers} computers assembled</li>";
echo "<li>{$partsLeft} parts left</li>";
echo '</ul>';
if ($money > 0) {
    echo "<p>Nakov gained {$money} leva</p>";
} else {
    echo "<p>Nakov lost {$money} leva</p>";
}