Question

Data Structures and Algorithms

You have been asked to develop a tracking system for a take-out Chinese restaurant. The owner would like to be able to enter orders into the system as they come in, mark them as completed when they are picked up, and maintain historical data for repeat customers.

What data structures should be considered? Lets brainstorm….

Answer 1

I would suggest Hashing data structure for this problem.

Hashing involves using an index/key that represents each individual item. Here, each order can be uniquely identified using a number, which is ORDERID. In such case, ORDERID will be the hash key.

Reasons for choosing hashing:

(i) Adding new orders:

While adding new order, the orderid can be sequentially generated automatically. For hashing, the insertion process has a time complexity of O(1), which is very efficient.

(ii) Marking the orders completed:

Using hash key lookup enables quicker retrieval of data. Hence, once the orders are picked up, the owner can mark the orders as completed by only providing the order id. Given an ORDERID, it only takes O(1) for average case to retrieve the info. Hence, it is the most efficient in searching.

(iii) Maintaining historical data:

As the number of historical records increase beyond a certain limit, re-hashing can be done. Re-hashing involves increasing the size of the hash table and moving all the historical data for repeat customers according to the new hash table. So, keeping the historical data for repeat customers in a separate place in the hash table will help in quicker and efficient access of historical data for repeat customers, which is O(1) (average case).