Did you fail your coding interview?

February 16, 2024 Shane Shown

Software engineers view coding interviews with a mix of trepidation and excitement. From conceptual questions to pair-programming sessions, the tech world abounds in unpredictable interview styles that could make or break your job search journey. There is no one answer for what makes an ideal approach — each situation calls for its own special blend!

Interviews for engineering and development roles can be quite the challenge — at times seeming more like a test of memory than problem-solving. While standards vary from company to company, often this means having candidates demonstrate their skills by writing code on a whiteboard while speaking aloud and explaining every step taken in real time; an old but still widely used method that doesn’t always offer jobseekers or employers the best insights into each other’s abilities!

Why Coding Interviews Are Standard

Coding interviews are a controversial topic that sparks strong reactions. Stories of interview experiences range from shocking to laugh-out-loud funny, but the overall sentiment is clear: technical interviews rarely demonstrate an individual’s true proficiency in their field. So if engineers’ tales have made you fearful or weary, take solace knowing others feel similarly!

Job interviews are a necessary evil, but many argue they don’t prepare software developers for the realities of their day-to-day. After all, who has time to write code on whiteboards when you’re tackling real world projects? Moreover, coding interview questions often cover topics never encountered in actual development work — making them more applicable to job interviewers than employers!

How often, for example, will a front-end developer specializing in React have to traverse a B-Tree in a specific, algorithmic way? Never, unless they’re doing something deeply wrong.

Candidates can leave interviews feeling empowered when they are presented with real-world problems to solve, as it gives them a chance not only to demonstrate their knowledge but also make an impact. Such coding assignments often bring out the best in candidates and provide exciting opportunities for making meaningful contributions.

Even more aggravating? Coding interviews are often entirely unfair. Even the creator of Brew — with tens of millions of installs — was invited to interview at Google and then rejected because he couldn’t solve a B-Tree problem.

Software engineers love to trick the interviewees and give extremely challenging questions. If you get the initial problem, it’s then common practice for an interviewer to throw a wrench in your solution, make the problem even harder, and create arguably unnecessary stress.

So why are they given?

For all their faults, coding interviews prove three things:

The candidate really wants the job and has put significant effort into preparation. If an interviewee hasn’t spent the time to get good at the process, it’s quite obvious. Companies want to hire people who put in the effort.
The software engineer can solve problems and actually code. Engineers who have to copy/paste scripts other people made or who don’t have enough experience with a language will often make big mistakes while problem-solving and coding up solutions.
The software engineer can effectively articulate their problem-solving. Engineers often will fail to solve the problem, only to find that they actually passed the interview. How? The interviewer decided their thought process was good enough.

How Coding Interviews Vary Across Companies

Highly successful companies understand the importance of effective recruiting strategies. In an effort to attract top talent, they create robust interviewing processes that not only reduce false positives but also weed out unsuitable candidates before they become bad hires and cause more harm than good. To secure their spot atop the recruitment ladder, these elite organizations often have some of most challenging interview standards in place!

Therefore, when you find that a hiring process especially easy, it’s likely the company has weaker engineering. This isn’t always true, of course, but it’s certainly something to keep in mind.

Landing your dream job takes more than just luck; you have to do some preparation! If the interview topic isn’t revealed, roll up your sleeves and be ready for any questions. Feeling overwhelmed? Don’t sweat it — simply reach out to recruiters or hiring managers with a direct request for additional information on what topics will appear in their interviews. Taking this extra step can make all the difference between leaving an impressive impression — and getting that new gig.

Preparation Is Everything! But How?

Being an interview pro takes patience and dedication — kind of like getting back in your workout routine after a long hiatus. Without consistent practice, you’ll quickly become ill-equipped when it’s showtime! Don’t worry though; if you’re prepared before the big day even arrives, no one will have to see any embarrassing moments as you head to the bathroom… or anywhere else for that matter. So grab those running shoes (metaphorically speaking) and hit refresh on all your skills so performance time is smooth sailing!

Without faith in yourself, the world of research and practice can be a daunting one. So keep running those laps — your future self will thank you.

If you want to work at a top tech firm, like Google or Facebook, we recommend you practice for:

Experienced engineer: four to six weeks, two hours a day
New engineer: six to eight weeks, three hours a day

For more mid-range companies, like Series A/B startups, you can usually get away with less preparation:

Experienced engineer: two to four weeks, two hours a day
Bootcamp graduate: four to six weeks, two or three hours a day

Yes, it is a lot of time, and you may be thinking, “do I really need to prepare that much?”

If you want to increase your chance at getting one of those elusive job offers, it’s essential that you put in 10% effort during preparation. And while the saying goes “no pain no gain,” even this amount of diligence won’t prevent failure entirely — so best prepare yourself and keep trying!

Some of the common topics

Trees
Hash tables
OOP, systems
Big O
Recursion
Stacks/queues
Arrays
Linked lists
Algorithms: BFS, DFS, binary search, merge sort, quick sort
Bit manipulation (few interviewers give these, but cover them anyway)

Expect questions relating to your experience as well: technologies, languages, frameworks, etc. SQL challenges and questions are very common.

Methods to Prepare

If you’re looking to pick up a new skill without breaking the bank, there’s no better place than the internet — it offers incredible training systems both free and paid.

Some of these sites include:

Geeks for Geeks — Free — If you’re looking to ace your technical interviews, this is the place. From start-up internships to high-level positions at top companies, they have everything you need for interview prep success!
Triplebyte — Free — Unlock job opportunities with your coding skills by taking a quick quiz! No resumé necessary — the company will auto-match you to companies that fit your requirements. Put yourself on the fast track for interviews and take charge of achieving success in tech today.
Pramp — Free — Get ready to see your coding skills soar! With their intuitive platform, simply tell them what you want to practice and they’ll help find the perfect pairing. Then get set for a 30-minute video session with another peer — where both of you can put each other through rigorous technical questioning using provided material by experts in the field (no more worrying about creating questions on your own!). After it’s all over, don’t forget to give feedback so that everyone involved learns something new — plus use it as an opportunity to gain confidence before facing recruiters during job interviews. Practice will make interviewing like a rock star look easy; then sit back while those dream offers come rolling in!
Interviewing.io — Free — Get prepped and primed for the tech job of your dreams, with interview practice from engineers at industry heavyweights like Google, Facebook & more! Get personalized feedback so you can hone all those interviewing skills — fast-tracking to top companies has never been easier.
Codefights — Free — It’s time to put your problem-solving skills to the test! Step into this arcade and get ready for an interactive experience — compete against peers or strangers, challenge yourself with interviews practices & tournaments, even go up against company bots. Get those gaming gloves on — it’s time for some serious fun!
My Code School — Unlock the full potential of a subject with thorough research. Get to grips with it so you won’t be caught out by any surprises!
Getboost.io — Tackle ~three easy practice problems and two hard practice problems, and review solutions until you understand them completely.

Training for interviews can be tough, but consistent repetition is key! Regularly revisiting topics will help develop an intuition around new problems so you’re well-prepared when the time comes. The most important thing to remember: no one said it would be easy — get started and push through those challenging moments.

How to Know When You’re Ready

When it comes to interviews, there’s no guarantee of success. Even the most organized and prepared individuals can stumble on their big day; so some risks have to be taken if you’re determined to stand out from the crowd.

Prepare to be challenged! Paying for a mock interview with an individual from a top company is well worth the effort. Get ready — their bar will be set high, but you’ll gain priceless feedback in return that can help guide your journey through future job interviews. It never hurts to go out and make some helpful connections either; with luck, maybe one of them will give you the expert advice you need.

With the job market more competitive than ever, it’s never a bad idea to give yourself an edge. Setting up interviews with companies that aren’t your top pick can be great practice for honing interviewing skills and getting comfortable in front of recruiters! Plus, you just might find out about some other opportunities along the way — who knows? Just make sure all those employers remain unaware of this sneaky tactic or they may not take too kindly to giving away their time like that! So happy hunting everyone — good luck on your search journey!

Other Resources

Do you want to understand how companies level their engineers? Check out the leveling guide from Nxt Level: https://www.nxtlevel.io/engineering-level-guide