Add Products to category by sku programmatically

Add Products to category by sku

<?php

// USAGE http://www.site.com/updategroupprice.php?price=14.95&sku=SKU123X

require_once '../app/Mage.php';
umask(0);
//Mage::app('admin');
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);

$sku = $_GET['sku'];
$id = $_GET['id'];
$categoryId = $_GET['catid'];

// get my products 

$productcollection = Mage::getResourceModel('catalog/product_collection');
$productcollection->addAttributeToFilter('sku', array('like' => $sku.'%'));
$productcollection->addAttributeToFilter("visibility", array("eq" => 4));

//Mage::getSingleton('catalog/product_visibility')->addVisibleInCatalogFilterToCollection($productcollection);

foreach ($productcollection as $product){

$product->setCategoryIds(array($categoryId));

$product->save();

echo $product->getSku()." has been added to Category ID: ". $categoryId ."<br>";

}

?>