How to Make Consistent Progress While Preparing for Coding Interviews

If you‘re preparing for coding interviews, you know how overwhelming the process can feel. With so many potential questions to study and skills to learn, how can you ensure you‘re making meaningful progress towards your goal?

As a software engineer who has interviewed hundreds of candidates at top tech companies, I‘ve seen many applicants stall out in their coding interview prep. They put in the hours but don‘t get the results they want.

The good news is that by following a few key principles, you can make sure your hard work translates into real improvement. Here‘s my expert advice on how to keep leveling up while studying for coding interviews:

Build a Rock-Solid Foundation

Before you dive into coding interview prep, make sure you have a strong grasp of fundamental computer science concepts. At minimum, you should be comfortable with:

• Basic data structures like arrays, linked lists, stacks, queues, trees, graphs, and hash tables
• Standard algorithms such as binary search, breadth-first search, depth-first search, recursion, and dynamic programming
• Big O notation and runtime analysis
• Object-oriented programming concepts like classes, inheritance, and polymorphism

If you have a formal CS degree, you likely covered these topics already. But if you‘re self-taught or need a refresher, invest time upfront to solidify your fundamentals. I recommend the classic textbook Cracking the Coding Interview by Gayle Laakmann McDowell as a comprehensive resource.

Online courses can also help you build a sturdy foundation. Choose rigorous, well-structured classes such as:

• Algorithms Specialization on Coursera
• Intro to Algorithms on MIT OpenCourseWare
• Data Structures and Algorithms Specialization on Coursera
• Algorithms, Part 1 and Part 2 from Princeton on Coursera

Don‘t just watch the lectures passively—engage with the material by doing assignments, taking quizzes, and implementing concepts in code. The more you apply what you‘re learning, the better you‘ll retain it.

Practice with Purpose

Of course, a strong theoretical foundation alone isn‘t enough to ace coding interviews. You need to practice applying those concepts to solve problems. But not all practice is created equal.

To get the most out of your problem-solving practice, be deliberate and strategic:

Use spaced repetition: When you learn something new, review it a day later, a week later, and a month later to move it into your long-term memory. Flashcard apps like Anki are great for this.

Identify your weaknesses: Keep a log of the topics and problems you struggle with and focus your practice there. Don‘t just stick to what‘s easy and comfortable.

Challenge yourself: As you improve, regularly attempt problems that are slightly beyond your current ability. Pushing your limits is key to growth.

Maintain a consistent schedule: Commit to a specific amount of practice time every day, even if it‘s just 30 minutes. Steady, regular practice beats sporadic cram sessions.

Reflect after each problem: After solving a problem, ask yourself what you did well, what you could improve, and what similar problems might be asked. Reflection enhances learning.

You can find an endless supply of practice problems on platforms like LeetCode, HackerRank, CodeSignal, TopCoder, and more. Start with the "Easy" category and work your way up as you improve.

Master Problem-Solving Techniques

In coding interviews, how you approach problems is just as important as whether you ultimately solve them. Interviewers want to see that you can break down tricky problems in a logical way.

To tackle any coding interview question methodically, try using the UMPIRE method:

1. Understand the problem statement. Ask clarifying questions if anything is unclear.
2. Match the problem to known patterns or categories, like Sliding Window or Two Pointers.
3. Plan your solution on the whiteboard or scratch paper before you start coding. Explain your approach out loud.
4. Implement your plan in code. Start with a naive solution and optimize if time allows.
5. Review your solution for bugs and edge cases. Step through an example input and confirm the outputs.
6. Evaluate the time and space complexity using Big O notation. Suggest further optimizations if possible.

Polya‘s Problem Solving Techniques can also help you approach tough problems:

1. Understand the problem. Identify the inputs, outputs, and constraints.
2. Devise a plan. Break the problem into subproblems. Sketch out examples.
3. Carry out the plan. Implement your algorithm and debug errors.
4. Look back. Analyze the solution. Consider other approaches. Discuss tradeoffs and extensions.

The more you practice these problem-solving methods, the more intuitive they‘ll become. You‘ll gain confidence in your ability to tackle even the trickiest questions.

Practice with Mock Interviews

Simulating real interview conditions is one of the best ways to prepare. That‘s why mock interviews are so valuable.

To set up an effective mock interview:

1. Find a friend, colleague, or professional interviewer to be the mock interviewer. Choose someone who has experience with technical interviews if possible.
2. Pick a coding question or two to focus on. You can find sample questions on sites like LeetCode or in Cracking the Coding Interview.
3. Set a timer for the length of a typical interview, usually 45-60 minutes. Treat the mock like a real interview, with the interviewer providing the question and you working through it as you would in the real scenario.
4. After the mock interview, debrief with your interviewer. Ask for specific feedback on what you did well and what you could improve.
5. Implement the feedback in your next mock interview and track your progress over time.

Professional interview prep services like interviewing.io and Pramp can connect you with anonymous mock interviewers if you don‘t have anyone in your own network. Some of these platforms even provide recordings of your interviews so you can evaluate your own performance.

The more you practice interviewing, the more natural it will start to feel. You‘ll gain poise, communication skills, and the ability to perform under pressure. Treat every mock interview as a learning opportunity.

Maintain Perspective

It‘s easy to get lost in the details of a coding problem. You might find yourself stuck on an edge case or worrying about the optimal runtime. But don‘t lose sight of the bigger picture.

Your ultimate goal is to make progress towards a complete solution. If you find yourself getting bogged down, ask yourself:

• Is this detail critical to the overall solution?
• Am I making meaningful progress on the core algorithm?
• Is there a simpler way to handle this case?
• Can I make a reasonable assumption to avoid this edge case for now?

Remember, a suboptimal solution is better than no solution at all. It‘s okay to mention that you‘d improve the edge case handling or runtime in the real world where you‘d have more time. The interviewer cares more about your problem-solving skills than minute details.

When you get stuck, take a step back. Draw some example inputs on the whiteboard. Brainstorm alternate approaches. Explain what you‘re thinking to the interviewer. Often, getting unstuck is as simple as rephrasing the problem or trying a different perspective.

Debug like a Champ

We all make mistakes while coding. What separates great engineers is how they handle those mistakes. Interviewers don‘t expect your code to be perfect on the first try. But they do expect you to be able to debug effectively.

When you think you have a complete solution, test it thoroughly. Walk through your code line by line with an example input, keeping track of the state of all your variables. Better yet, use formal unit tests to check edge cases.

If you find a bug, don‘t panic. Calmly and methodically isolate the issue:

1. Identify the symptom. Is the error a compile-time error, a runtime exception, or an incorrect output?
2. Find the line of code where the error occurs using print statements or a debugger.
3. Analyze why that line is causing an error. Is it using the wrong variable? Are you accessing an array out of bounds?
4. Implement a fix and retest the code to make sure the error is resolved.

Talk through your debugging process out loud so the interviewer can follow along. They care more about how you approach problems than whether you make mistakes.

With practice, debugging will become second nature. You‘ll be able to quickly identify and resolve issues in your code, demonstrating your value as an engineer.

Embrace a Growth Mindset

Studying for coding interviews is a marathon, not a sprint. Some days you‘ll feel like you‘re making huge strides. Other days you‘ll feel stuck or like you‘re moving backwards.

That‘s all part of the process. Remember, the goal is consistent, incremental progress, not perfection.

To stay motivated in the face of challenges:

• Acknowledge that struggling with hard problems is part of the learning process. It doesn‘t mean you‘re not smart or cut out for this.
• Celebrate your successes, even the small ones. Solved a problem faster than last time? Identified a bug all on your own? Those are wins!
• Focus on your growth over time, not getting every problem right. Track how many problems you‘re solving each week or your percentage improvement on timed tests.
• Join a community of developers preparing for interviews, like the LeetCode forum or the cscareerquestions subreddit. Seeing that others are facing the same challenges can be reassuring.
• Take care of yourself outside of interview prep. Exercise, eat well, spend time with loved ones, and pursue hobbies. Studying is important, but it shouldn‘t consume your entire life.

Remember, this is a skill you‘re building for the long term. With steady, strategic effort, you‘ll be nailing coding interviews before you know it. Trust the process and keep putting in the reps. You‘ve got this!

Your coding interview questions, answered:

Before we wrap up, let‘s review some frequently asked questions about the coding interview preparation process.

How long should I spend studying for interviews?

Expect to spend at least 3 months of consistent practice, for several hours a week. If you have less experience or are aiming for highly competitive companies, give yourself 6 months to a year to fully prepare.

How much time should I spend on each practice problem?

During your practice sessions, don‘t let yourself get stuck on any single problem for more than 30 minutes. If you‘re truly stuck, find a similar solution and understand it before moving on.

Should I look up answers if I‘m stuck?

It‘s okay to consult solutions for problems you‘re really struggling with, but don‘t make it a habit. Spend time wrestling with the problem on your own first. When you do look at a solution, focus on understanding the approach, not just memorizing the code.

Should I apply to companies while still studying?

Start applying for your top choice companies when you can solve most "Medium" problems on LeetCode within 30 minutes. Until then, focus on building your skills. You only get one shot at each company, so make it count.

I can solve problems, but I‘m not fast enough. How do I get quicker?

Speed comes with repetition. The more problems you solve, the faster you‘ll pattern match and implement solutions. Time yourself on practice problems and work on beating your own times. Learning keyboard shortcuts for your preferred programming language will also help you code faster.

What should I do if I forget a concept during an interview?

Take a deep breath and try to reason through the concept from first principles. If you‘re totally blanking, it‘s okay to tell the interviewer you‘re a bit rusty on that topic and ask for a reminder. They may deduct some points, but it‘s better than giving up entirely.

How do I keep track of all the problems I‘ve solved?

I recommend keeping a problem-solving journal where you record the prompt, your solution, and any key insights for each problem you solve. Review this journal periodically, especially for problems you struggled with. LeetCode also lets you bookmark problems and record your solutions.

I hope this advice helps you streamline your coding interview prep and start seeing the progress you deserve. Remember, you‘re building an invaluable skill set that will serve you throughout your entire career. It‘s a challenging process, but you‘re more than capable of rising to that challenge.

Keep putting in the focused work, day after day, and before you know it, you‘ll be accepting your dream job offer. I‘m rooting for you every step of the way!