Orders

<?php

$productsAndPrices = [];

$cmd = explode(' ', readline());

while ($cmd[0] !== 'buy') {
    $product = $cmd[0];
    $price = floatval($cmd[1]);
    $quantity = intval($cmd[2]);

    if (!key_exists($product, $productsAndPrices)) {
        $productsAndPrices[$product] = [];
        $productsAndPrices[$product][1] = $quantity;
        $productsAndPrices[$product][0] = $price;
    } else {
        $productsAndPrices[$product][0] = $price;
        $productsAndPrices[$product][1] += $quantity;
    }
    $cmd = explode(' ', readline());
}

foreach ($productsAndPrices as $products => $priceAndQuantity) {
    printf("%s -> %.2f\n", $products, array_product($priceAndQuantity));
}