When trying to land a software engineering job, you'll probably have to go through several interviews, including behavioral and system design. But at the end of the day, it all comes down to one thing: your coding skills. Your proficiency in coding is the key factor that will determine if you're the perfect fit for the role.
Regardless of your experience level — whether you're a seasoned developer or fresh out of university — nailing a coding interview can be tough, but persistence and hard work pay off. As someone who landed an offer from Facebook after a full year of preparation, I know this firsthand. In this article, I'd like to share with you some tips and strategies that I learned along the way.
Let’s dive in.
Tip #1 — Practice Coding
In your day-to-day work as a software engineer, you might not be using algorithms and data much. Still, they are essential basics that you need to know. So how do you get good at those? Learning algorithms and data structures can be challenging, but it's no rocket science or secret art. The main issue is the amount of time it takes to learn them, so planning and practice are key.
Think of improving your coding skills like building up your muscles. You can't expect to get all ripped and toned in just a few weeks of intensive exercise. Similarly, you won't master algorithms in a matter of days. The key is to put in consistent and steady effort over a long period to get the results you want.
Back in 2019, when I started preparing for coding interviews, I was clueless about how to write even the most basic algorithms, such as Binary Search. It took me around six months of consistent practice to get my first onsite interview with Google. How did it go? I failed.
But did I give up? No. I kept practicing for another year until I finally got an offer from Facebook (which we now know as Meta). So, the bottom line is that learning these skills takes time and effort, but the payoff can be life-changing!
When you first begin working on coding problems, it's perfectly normal to feel a bit overwhelmed. You might even catch yourself thinking, "What’s wrong with me? Why can’t I solve even the simplest problem?" That’s just a natural part of the learning process. You’ll get better over time.
A helpful and time-tested strategy to deal with the feeling of overwhelm is to break a large task into manageable chunks and set achievable goals.
I recommend starting with 1-2 Easy or Medium-level problems each day and spending around 15-30 minutes on each one. This will help you build your problem-solving skills gradually and avoid getting overwhelmed. Once you start to feel more confident, you can increase the intensity by tackling up to 3-4 problems per day.
To give you an idea of what's possible with consistent practice, I personally solved around 200 problems (50% Medium, 40% Easy, 10% Hard) over a year before I got my first offer from a Big Tech company. Keep in mind that everyone learns at their own pace, so make sure to determine the amount of practice that works best for you. The important thing is to stay focused and keep at it.
If you want to find excellent resources to practice coding and sharpen your interview skills, there are several options you can consider. Some of the best are Leetcode, Hackerrank, and Codeforces — these platforms offer a variety of challenging problems that can help you hone your coding abilities.
But if you need more structure or guidance, there are also resources like Interviews.school or paid courses such as Algoexpert.io. These can be especially helpful if you're just starting out or if you're unsure of where to begin.
I have used all of these resources during my own journey of interview preparation and can vouch for their quality.
Tip #2 — Know your programming language
It's important to have a solid command of the language you'll be using so that you showcase your technical skills and problem-solving ability to the fullest. Usually, you get to choose the language for your algorithmic coding, but sometimes the interviewer may have specific language requirements. Make sure to check that beforehand.
Use the language you're most comfortable with, even if it's not your primary one. Make sure you know its common data structures, shortcuts, and memory management. My choice for coding interviews is Python, although I work with PHP daily. Python's easy syntax helps me prototype solutions quickly, and I don't have to worry about things like $ signs, brackets or semicolons.
To improve your skills in your programming language, spend time learning its fundamentals, practicing coding, and studying other programmers' solutions. I recommend checking out Leetcode — in its Comments and Discussions section, you can find some great examples and techniques to learn from.
Tip #3 — Ask clarifying questions
Don't rush into solving a problem without asking questions first. This is a common mistake that can be a red flag for interviewers. Ask a few clarifying questions even if you feel confident you understand the problem correctly.
Coding problems are intentionally ambiguous, and interviewers won't provide all the necessary details upfront.
Instead, interviewers expect you to clarify details, so ask a few questions to make absolutely sure you and the interviewer are on the same page.
Besides, this way you’ll be able to identify and clarify edge cases. For example, you may want to ask about the format of the input, the data types involved, or whether the problem has any constraints. Knowing specific details can save you time and allow you to focus on the task at hand.
Tip #4 — Talk through your solution before coding
When you're solving a problem in an interview, don't rush to start coding. Take a moment to talk through your solution first. This will help you clarify the problem and make sure you have a solid plan before you dive in. Talking it out can also save you time and prevent you from making unnecessary mistakes.
I've almost fallen into this trap myself. In one interview, I was asked to implement string prefix matching. I immediately thought of a rather complex solution that involved a Trie. But once I began to describe my idea out loud, the interviewer stopped me and asked for a simpler way that just involved iterating over two strings.
If I had started coding right away, I would have wasted time on an overcomplicated solution that the interviewer was not even asking for.
Once you have talked through the solution and the interviewer is satisfied with it, only then you can start implementing it.
Tip #5 — Communicate
During a coding interview, the interviewer is not so interested in whether you actually arrive at the solution.
They want to see how you approach the problem-solving process.
Make sure to spell out your thinking and explain your reasoning as you go.
Remember that the interviewer is on your side and is there to help you succeed. Think of the interview as a team effort, where you and the interviewer are working together to find a solution. You should be doing most of the talking, though (around 70-80% of the time). The interviewer may occasionally provide feedback or correct you. Be open-minded and willing to learn from the interviewer's feedback, using it to your advantage.
Be friendly and responsive throughout the interview. If you need a moment to focus, let the interviewer know. Take a brief pause to collect your thoughts, but don't let it drag on for too long.
Tip #6 — Test your solution
Don't forget to rigorously test your code once you've finished. Testing is important to help catch any mistakes or issues you might've missed.
To ensure your code produces the expected output, use the example inputs provided by the interviewer. Consider testing edge cases, including input boundaries, formatting or type of inputs, empty, null, or negative values, and inputs that are too small or too big.
When you're testing, go through your code line by line and check the values of variables and expressions. This way you will catch errors that are challenging to spot by merely taking a glance at the code.
After you've tested everything, take a step back and think about how you can make your code even better. Maybe there's a more efficient way to solve the problem, or you can make the code easier to read and understand.
Conclusion
Coding interviews are a challenge but you can greatly improve your chances of success with thorough preparation and practice.
Let’s recap the key takeaways:
- Study the fundamentals;
- Know your language;
- Ask clarifying questions;
- Talk through your solutions before coding;
- Test your solution thoroughly;
Stay calm and approach the interview as a collaborative problem-solving process.
Best of luck in your future coding interviews!
The lead image was generated using HackerNoon's Stable Diffusion AI Image Generator feature, via the prompt "a coding interview at facebook".