Stop chasing hard problems: Why focusing on fundamentals is the key to cracking interviews

When preparing for a technical interview, many SWE candidates prioritize solving the toughest problems, thinking that if they can tackle the hardest questions, they’ll be ready for anything. 

This approach often backfires. 

At Formation, we’ve seen firsthand that mastering the fundamentals is a far more reliable way to build the skills needed to succeed in an interview. 

Here’s why honing your foundational problem-solving skills is the most effective preparation strategy.

Problem-solving skills matter more than solving the problem itself

One thing I see all the time is people trying to memorize problems for their technical interviews. They go on sites like LeetCode, find the questions tagged for a specific company, and try to hammer those into their memory. It might seem like a good idea, but interviewers aren’t looking for whether you’ve memorized the answer to a specific question—they want to see how you think through a problem you haven’t seen before.

The truth about technical interviews is that they’re designed to evaluate your problem-solving skills, not your ability to recall answers. If you’ve seen the question before and solve it too quickly, a good interviewer will catch on. In most cases, they’ll just give you another problem because they haven’t learned what they need to learn from you yet. Memorizing answers isn’t going to help you in that situation. What’s more important is being able to use your problem-solving tools effectively under pressure.

You need to build a mental toolbox full of techniques you can apply in different ways to solve new problems. This is where the real value of interview prep comes in. 

Fill your toolbox: The pyramid of problem-solving

One of the most common mistakes I see candidates make is spending too much time on hard problems, thinking that this will prepare them for the hardest questions an interviewer might throw their way. While chasing the more complex challenges is tempting, the key to interview prep lies in a pyramidal approach. This strategy starts with a strong foundation of easy problems and gradually builds up to more difficult ones. Here’s how it works.

At the base of the pyramid are easy problems. They might seem simplistic, but these problems reinforce the most important techniques—those that are at the core of nearly every interview question you'll face. Mastering these easy problems ensures that you have a solid grip on fundamental concepts and builds basic coding fluency. Without a strong foundation, tackling harder problems is like trying to build a house without a strong base. Everything collapses.

As you move up the pyramid, you can tackle medium problems. These challenges combine fundamental techniques with more complex scenarios, which are closer to the types of questions you’re likely to encounter in a real interview. Medium problems force you to apply basic skills in creative ways.

Finally, at the top of the pyramid are the hard problems. These should not dominate your prep. While it’s good to challenge yourself, spending too much time on hard problems drains your mental energy and can give you a false sense of what matters most in an interview setting.

Solving harder problems isn’t the answer

Spending too much time on hard problems can be both mentally exhausting and inefficient. These problems often introduce nuances that rarely come up in interviews, meaning candidates waste time on concepts that might never be asked. Hard problems take longer, so you'll get through fewer of them and, therefore, practice fewer topics. For someone who is struggling, they also can reinforce impostor syndrome. Frustration and burnout are common results of this approach, which can also hurt your confidence going into an interview.

Instead, easy and medium problems better prepare you for the types of foundational questions most interviewers will ask. They might seem repetitive, but this repetition is where you build fluency. It’s where problem-solving becomes second nature.

In fact, many medium-level problems in interviews are just combinations of two or three fundamental techniques. This reinforces the importance of focusing on the basics—you need to know them inside out to effectively combine them and solve more complex problems on the spot.

The value of foundational problems

A clear example of this can be found in data we’ve gathered from our Technical Interview Readiness Assessment (TIRA). Our data shows that candidates generally excel in solving array-related problems, which is understandable—arrays are a fundamental data structure that appears frequently in interviews.

However, string problems, which are essentially arrays of characters with a few additional rules, trip people up far more often. Why? Strings are introduced early in learning but often aren’t revisited enough. Candidates assume they understand them, but the nuances in handling strings often expose gaps in their foundational knowledge.

This shows why revisiting these “basic” topics, like arrays, strings, and other core data structures, is so critical. What seems simple at first often has layers of complexity that you may overlook, leading to mistakes in interviews as they create the foundation of most problems.

How to consistently reinforce fundamental skills

Mastering the fundamentals requires consistent practice. Working on easy problems isn’t just about arriving at the right answer—it’s about deeply understanding why your solution works and being able to explain it clearly. This is the focus of Formation’s peer group sessions, where you can practice with others, receive feedback, and improve both your technical skills and communication.

While it’s important to stretch your abilities with harder problems occasionally, your main focus should be the core topics underlying most interview questions. By making these your priority, you’ll approach any problem with confidence, knowing you’ve built a strong foundation.

Get holistic interview prep with Formation

The Formation Fellowship gives mid-level and senior engineering job seekers everything they need to land their dream roles—including personalized skill brush-ups, resume help, unlimited mock interviews with experienced software engineers and hiring managers from top-tier tech companies, career and negotiation support, and more. 

If you’re having trouble navigating your job search on your own, apply here and get unconditional support from a team of engineering mentors, technical recruiters, career coaches, and more.