what is the best way to count product per category in cart woocommerce?

I would like to check item gonna be add to cart is already in cart and belong to which category, if that category have over 5 products then throw an exception message:

function check_product_in_cart() {
//Check to see if user has product in cart
global $woocommerce;

// start of the loop that fetches the cart items

foreach ( $woocommerce->cart->get_cart() as $cart_item_key => $values ) {
    $_product = $values['data'];
    $terms = get_the_terms( $_product->id, 'product_cat' );

    // second level loop search, in case some items have several categories

    $cat_ids = array();

    foreach ($terms as $term) {
        $cat_ids[] = $term->term_id;
    }

    if(in_array(434, (array)$cat_ids) || in_array(435, (array)$cat_ids)) {

      //category is in cart!
       $product_in_cart = true;

     //count the category?
       $count = 1;
       while($product_in_cart === true) {
           $count +=1;
       }
    }
}

return $product_in_cart;
return $count;

}

then echo out the error message can not add to cart. what is the best way to count product in cart per category?. Basically, I want to limit item add to cart per category. Thanks guys