Coding Interview Guide

Even the most experienced developers sometimes get cold sweats at the thought of going through a coding interview. You can study for four years at a prestigious university, get a master’s degree, or enjoy considerable experience in the field—and still get stymied by a coder interview question that’s outside your area of expertise.

Coding for interviews is almost entirely unlike coding in real life. In the real world, you can spend days or months working through a complex or unfamiliar problem, but the technical hiring process simply won’t allow you the luxury of time. If you’re faced by a question you don’t know the answer to, you may end up watching your dream job slip away as the clock ticks down.

Coder interviews don’t have to be stressful, however. Using our coder interview practice guide below, you’ll be able to secure an interview, impress your reviewer, and master some of the most common software engineer interview questions.

Getting an Interview

First, do some basic preparation. Make sure your resume is up to date. Double-check your website or portfolio to make sure that it demonstrates your most recent, relevant, and interesting projects. Polish your LinkedIn profile and lock down any social media accounts where you share personal opinions. In short, make yourself look employable.

If your first few attempts at sending a resume are met with silence, it’s time to refine your approach. Make sure that what you’re putting down on your resume is what your recruiters want to see. Make an effort to network with people who work at your most exciting job opportunities. Lastly, polish up your LinkedIn profile. Recruiters love to see a fleshed-out LinkedIn page, as it makes their jobs much easier.

The last—and probably important—part of getting a coding interview is doing research about the companies where you’ll apply and jobs they have available. What languages do they most commonly use? What is the major challenge that their output is trying to solve? How do they treat their workforce? If hired, will there be others who can share your expertise? 

Because the coder interview process can often be grueling or drawn-out (regardless of the working environment that the company provides), it’s important that you apply only to companies where you really want to work. Otherwise you’ll be so overwhelmed by the technical hiring process that you may burn out before you get a job offer.

The Coding Interview Process

It’s important to remember that the technical interview process barely resembles the interview process for a more traditional job. Your coder interview is all about coding skill. Sometimes, people even complain that the questions asked during a coding interview don’t necessarily reflect the skills required for their job.

Traditionally, coder interviews were staged in two parts—a short phone screen and an in-person interview. Through most of 2021, however, you can probably expect an online code interview during both stages of the process. The screening interview is mostly designed to weed out bad candidates. It will last only an hour at most, and the questions may be a bit simpler—again, they’re just trying to weed out people who lie on their resumes.

Expect the second coder interview to be much longer—up to several hours long. Here, the goal is to understand more than whether you can understand technical questions, but whether your thought process is a fit for the organization. You’ll be asked to communicate the steps you’re using to solve your problem as you solve it, and you may have multiple interviewers who will each ask different questions.

This is often a grueling process, but if you follow our coder interview practice guide, you’ll be able to stay sane. 

Picking a Language

When it comes to coding for interviews, the best practice is to pick one language and stick with it for all of your assessments. Although some companies tend to focus on one language over another, it’s acceptable to pick whatever language you want during the coder interview, even if the company doesn’t use the language all that much.

With that said, you really want to choose a language that’s easy to code in, especially as many companies choose not to use a traditional IDE during the technical interview process. Languages that lack sophisticated library functions and data structures are harder to code with in a time-limited setting, as are languages that require lengthy expressions. By contrast, languages such as Python are ideal for coder interviews because you can get more things done with fewer keystrokes.

This said, not everyone is familiar with Python. Nearly every developer, however, is familiar with either Python, Java, or C++. While Java and C++ are a bit slower than Python, they’ll still get the job done, and in the end your familiarity with them will matter more than the speed with which you can type.

Reviewing the Basics

First, be ready to answer many questions related to data structures and algorithms. Even if your specialization doesn’t require a lot of knowledge in this area, knowing about this material will make you a better programmer. Your knowledge of algorithms and data structures will demonstrate that you can write efficient code that runs quickly, something that will impress your assessors.

In addition, your online code interview might also contain questions about other computer science fundamentals such as operating systems, system design, and networking. It’s quite common that applicants will over-prepare for questions about algorithms without knowing much about the systems they’ll be running on. Answering them will demonstrate that your talent isn’t all in one area.

Lastly, questions about your resume and experience will probably take the least amount of time during a technical interview, but it’s important to have answers prepared regardless. Your attitude, rather than your answers to these questions, will probably have more to do with whether you get hired. Interviewers want to see candidates who are smart, humble, and willing to take direction.

Common Questions to Be Prepared For

Based on our experience running the technical interview process for thousands of candidates, some of the most common software engineer interview questions we encounter include:

  • Breadth-First Search algorithms
  • Hash table implementation
  • Palindrome checker
  • Moving-window average algorithm
  • Sorted lists of numbers

In other words, logic, algorithms, and complexity are all very important to technical hiring. Anyone who says that these questions aren’t necessarily relevant to the day-to-day reality of being a front-end developer is definitely not wrong, but for now, this is how the game is played. 

If it’s been a while since you’ve studied these questions, or if you didn’t take classes on algorithms in college, then your best bet is to start practicing using one of the many free tools available on the internet.

Coding Interview Practice

Here at CoderPad, we aim to improve the technical interview process in ways that make life easier for both applicants and recruiters. By offering a platform that emulates an IDE and works remotely, we let applicants answer more complex questions faster, letting them demonstrate more of their thought process than a whiteboard ever could. With a single-click remote interview functionality, we make it easier than ever to evaluate candidates from any part of the world at any time. This means that recruiters can interview a wider range of talent, and candidates have a better opportunity to demonstrate their skills and knowledge.