Coding Interview Topics in 2023

When applying for a job as a programmer, employers need to validate your skills and technical know-how. You may be a skilled programmer but fumble at interviews because you don’t know where the questions will come from and don’t prepare accordingly.

This article will look at the most popular coding interview topics–essential subjects in programming that employers can use to test your ability. Read on to discover where possible questions for your next interview may come from so you are better equipped to ace the test.

1. Array

An array is a sequence of data structures containing items of identical data type, like variables, identified by an array index. Arrays can have multiple axes, and each axis has its dimensions. For instance, a one-dimensional array is called a list. Conversely, a two-dimensional array is a table–a familiar example is an Excel spreadsheet package.

Hence, knowledge of arrays and their application is essential. Thus, employers may test your knowledge of arrays to gauge your understanding of data organization.

2. Data Structures

A data structure is a well-organized sequence of gathering, sorting, processing, storing, and analyzing data. Data structures can be in basic or advanced types, but generally, all data structures organize data for a specific purpose. Thus, it makes data access and acquisition more straightforward, framing information organization so that humans and computers can understand. 

Data structures help organizations access and manipulate data in appropriate ways easily. For example, employers may request you build or explain the process of creating data structures. Therefore, learning how to make basic and advanced data structures is essential for companies.

3. Stacks

A stack is a list structure that carries a linear sequence of elements. In other words, it is a data structure where items are added or removed only from the top. Thus, it follows a last-in-first-out (LIFO) format.

Push and Pop are the terms used to define adding and retrieving data packages from a stack. Calling a function pushes it onto the stack, and removing it pops it off. As said earlier, this only occurs at the top of the stack.

Stacks enable you to evaluate commands that include operands and operators. They also allow you to check an expression for parenthesis matching (i.e., backtracking). You can use it to convert expressions from one form to another and for systematic memory management. Understanding stacks and their applications will serve you well–especially when you attend an interview.

4. Linked Lists

A linked list represents data elements connected linearly but whose order is not determined by their physical arrangement in the memory. Also, it is a data structure consisting of components called nodes linked together.

Linked lists allow for efficient memory utilization and storage of extensive data, amongst other functions. Furthermore, linked lists aid the development of web browsers, music players, image viewers, and back buttons. Hence, understanding how you can apply it in improving the storage memory of a company, linking different organizational data, and other helpful applications will help you immensely.

5. LIFO/FIFO

Last-In-First-Out (LIFO) and First-In-First-Out (FIFO) represent a method of managing data structures. As their names imply, LIFO means the last item is processed first and the first item last. Conversely, FIFO indicates that the first item will be processed in the same sequence until it reaches the starting component. The data structures Stack and Queue also represent LIFO and FIFO.

Many businesses across different industries apply the FIFO/LIFO principle in their daily operations. Therefore, utilizing the LIFO/FIFO principle in creating technological solutions is a great way to leave a mark on an organization. 

6. Queue

A queue consists of elements maintained in a sequence or linear arrangement and configured by adding items in the series or popping them from the other end of the series. Queue’s principle of operation makes it a first-in-first-out (FIFO) data structure. Adding an item to the back of the queue is called enqueue while deleting an item from the front is called dequeue.

Queues have various applications, including multi-programming, task scheduling, networking, and sharing resources. In an organizational setting, queues allow the efficient management of bulk data, aids ease of access to a particular service used by many customers, allow for quick data inter-process communication, and are used to implement other data structures. Thus, you should know how to utilize this data structure in a company.

7. Recursion

Recursion is a data analysis process that solves a complex problem by dissecting it into smaller components, so it is analyzed bit by bit until the entire issue is solved. Thus, recursion enables a function to call its code by itself, and the resulting function is termed a recursive function.

Recursion enables you to solve different programming challenges; as long as it has happened before, this method helps you to solve it again. Furthermore, recursion makes code easier to write, eliminates unnecessary function calling, and rectifies data structure problems. Thus, your knowledge of recursion will help you develop solutions to naturally recursive or repetitive tasks in a company.

8. Binary Trees

A binary tree is a branched, non-linear data structure with a parent node carrying a maximum of two children. With every data element, there are two nodes that either branch left or right. The node at the top of others is the root node, while the node that holds sub-nodes is called the parent node.

The three primary constituents of the nodes in a binary tree are the data element, right reference, and left reference. Binary trees are applied in hierarchical data storage and present a more flexible way of handling and sending data. Furthermore, it enables hashing, routing data for network traffic, data compression, preparing binary heaps, and search trees. These applications are handy in large organizations. Hence, you should be familiar with binary tree applications, as you must apply them in your programmer job.

9. Object-oriented Programming

Object-oriented programming is a coding paradigm that involves “objects” that contain data and code. Today’s most widely-used and top programming languages (like C++, Java, Python, etc.) are multi-paradigms and support object-oriented programming, typically combined with imperative and procedural programming. Thus, this shows the importance of object-oriented programming, especially when learning how to code.

Amongst its many applications, it is a practical problem-solving approach, supports the development of flexible applications, aids troubleshooting, and allows for code recycling. Seeing its importance in the tech world, it is likely that you will be thrown questions on OOP to confirm the extent of your knowledge on the subject in your following tech interview. Therefore, learn in detail what object-oriented programming is before the interview. 

10. Linear and Non-linear Data Structure

A Linear data structure has data elements interconnected in a sequential pattern. It is easy to implement because computer memory follows a sequential process, too. Linear data structures include lists, queues, stacks, arrays, etc.

A non-linear data structure, on the other hand, has no set sequence of connecting all its elements, and each part can have multiple paths to link to other components. Such data structures support multi-level storage but are often not traversed in a single run.

Understanding how linear and non-linear data structures work and the best way to apply them allows you to create robust application software and effective data models— these are significant needs of many companies. Moreover, it is a test of your coding knowledge and expertise.

Coding Interview Topics in 2023 – Final Thoughts

The topics highlighted in this article comprise the bulk of probable coding questions you’ll likely be asked about during your next interview. Study them thoroughly so you are better prepared to tackle any questions you get. 

Conversely, researching a potential employer before interviewing is crucial too. You don’t want to sound uninterested or ignorant of the organization during your interview–that’s not a good first impression. So, research the company’s background and needs and how you can help solve them with your coding knowledge. That way, you increase your chances of getting hired.