Algorithm · Karat · Medium
You receive three tables, each supplied as a 2D array of strings: Customers: name, email, product, quantity. Each customer is associated with exactly one product. Orders: user id, email (which may be null), and the order total. Products: product name and unit price. Build a mapping from each order's user id to the corresponding customer name. When an order carries an email, it can be linked to a customer directly by matching that email. When the email is null, the order must…