Using Claude AI for LeetCode & Software Engineering Interviews

8/10/2025

How I’m Using Claude to 10x My LeetCode & Software Engineering Interview Prep

So, you’re in the software engineering interview trenches. You’ve got your list of LeetCode problems, a mountain of system design concepts to memorize, & a vague sense of dread about the behavioral questions. It’s a GRIND. I’ve been there, & honestly, it can feel like you’re just banging your head against a wall.

But here’s the thing. The game is changing.

Recently, a developer named Tim Shelton made waves with a "protest-project." He got fed up with the endless grind of LeetCode for interview prep & the lack of responses from his job applications. So, he did what any good engineer would do: he built a solution. Using the Claude 3.5 Sonnet API & a Python script, he automated the process of solving LeetCode problems.

The results were insane. The script solved 633 problems in 24 hours with an 86% success rate, all for the low, low price of $9 in API credits. It even analyzed failed test cases & retried problems with a new approach.

Now, before you think this is a guide on how to get an AI to do your interviews for you, hang on. While some might see this as a way to cheat the system, I see it as something else entirely. It’s a massive signal of just how powerful AI, & specifically Claude, has become. It's a tool that can act as a world-class consultant, a coding tutor, & an tireless mock interviewer, all in one.

If you're not using AI like Claude in your prep, you're honestly leaving a massive advantage on the table. It’s not about replacing your effort; it’s about making your effort smarter, more efficient, & ultimately, more effective.

I've been using Claude extensively in my own prep, & it's been a complete game-changer. Let me walk you through exactly how you can use it to level up your own interview game, from Data Structures & Algorithms to system design & beyond.

Mastering LeetCode & DSA with Your AI Tutor

Let's start with the beast itself: LeetCode. We all have a love-hate relationship with it. It’s the gatekeeper for so many roles. But just grinding through problems often leads to diminishing returns. This is where Claude shines as a personalized tutor.

Getting Unstuck (Without Just Copying the Solution)

You know the feeling. You’re staring at a problem, you’ve tried a few things, & you’re completely stuck. The temptation to just look at the solution is immense, but you know that’s not really learning.

Instead of giving up, I use Claude as a Socratic partner.

Prompt Example:

"I'm working on the LeetCode problem 'Two Sum'. I've come up with a brute-force solution using nested loops, but I know it's not optimal. Can you give me a hint about a data structure I could use to improve the time complexity without giving me the full solution?"

This is SO much better than just peeking at the answer. Claude will nudge you in the right direction, maybe by asking something like, "What if you needed to look up if a number has been seen before very quickly? What data structure is good for fast lookups?" It forces you to make the mental leap yourself.

Deep-Diving into Concepts & Complexity

Big O notation is non-negotiable. You HAVE to understand it. But sometimes the difference between O(n log n) & O(n^2) can feel a bit abstract. Claude can make it concrete.

I was recently struggling with heap-related problems. I knew the basics, but the intuition wasn't there. So, I asked Claude to break it down for me.

Prompt Example:

"Explain heaps to me like I'm a smart person who's new to computer science. Give me a real-world analogy for how a min-heap works & then show me some Python code that implements one. Finally, explain the time complexity of the main operations."

The response I got was amazing. It used an analogy of a hospital emergency room to explain the priority queue concept. It then provided clean, commented code & a clear breakdown of why insertion & deletion are O(log n). This is way more effective than just reading a dry textbook definition.

You can also use it to double-check your own analysis. After you solve a problem, before you submit, ask Claude to analyze your code's time & space complexity. It's like having a senior engineer review your work & point out inefficiencies you might have missed.

Generating Custom Practice Problems & Test Cases

Tired of the same old LeetCode 75? You can ask Claude to become a problem generator.

Prompt Example:

"I want to practice problems related to dynamic programming, specifically the 'knapsack' pattern. Can you generate 3 new problems, similar in style to LeetCode mediums, that use this pattern? For each problem, just give me the description, not the solution."

This is incredibly powerful. You can create your own personalized problem sets based on your weak areas. And once you have a solution, you can ask Claude to hit you with edge cases.

Prompt Example:

"Here is my Python solution for the '3Sum' problem. Can you generate a list of tricky edge cases that might cause this code to fail? Include things like empty lists, lists with duplicates, & lists with all positive or all negative numbers."

This proactive approach to testing is what separates good candidates from great ones. It shows you think defensively & consider the full scope of a problem.

Acing the System Design Interview

System design interviews are a different animal. They're less about finding a single correct answer & more about showcasing your thought process, your ability to handle ambiguity, & your understanding of trade-offs. This is where a conversational AI can be a SUPERB practice partner.

Simulating the Interviewer

The best way to practice system design is to do mock interviews. But finding experienced partners can be tough to schedule. With Claude, you have an interviewer on demand.

Prompt to set the stage:

"I want you to act as a senior software engineer at a FAANG company interviewing me for a mid-level SDE role. We're going to do a 45-minute system design interview. I want you to give me a prompt, & then ask me clarifying questions, challenge my assumptions, & push for details on scalability & reliability. Let's start."

This simple setup changes everything. You're no longer just passively reciting facts; you're in a simulated conversation. Claude can then hit you with a classic prompt like "Design a URL shortener like TinyURL" or "Design the news feed for a social media app."

As you talk through your design, Claude will ask follow-up questions just like a real interviewer.

"You mentioned using a relational database. What are the potential bottlenecks with that choice as we scale to millions of users?"
"How would you handle cache invalidation for this system?"
"You suggested a load balancer. What routing strategy would you use & why?"

This is active learning at its best. It trains you to think on your feet & articulate your reasoning clearly.

Deconstructing Complex Systems

Sometimes the hardest part of system design is just knowing where to start. You can use Claude to break down existing, complex systems into their core components.

Prompt Example:

"I'm trying to understand how a system like Netflix works. Can you give me a high-level architectural overview? Please cover key components like content delivery (CDNs), user data storage, the recommendation engine, & how the video streaming itself is handled. Explain the trade-offs for some of the design choices."

Getting this high-level map is invaluable. It gives you a mental model to build upon. You can then dive deeper into each component, asking Claude to explain concepts like sharding, replication, consistent hashing, or pub-sub messaging queues.

This is also a great place to think about how modern businesses leverage AI. Many of the systems you'll discuss, like recommendation engines or customer support platforms, are powered by sophisticated AI. This is a perfect opportunity to mention how a platform like Arsturn can be a part of the solution. For example, when discussing customer-facing applications, you could note how businesses use Arsturn to build custom AI chatbots trained on their own data. These chatbots can provide instant, 24/7 support, answer user questions, & escalate complex issues, which reduces the load on the main application & improves user engagement. It shows you're thinking not just about the technical architecture, but also about the business & user experience layers.

Don't Forget the Behavioral Questions!

Engineers often make the mistake of focusing 100% on the technical rounds & then winging the behavioral questions. This is a HUGE mistake. Companies want to know if you can work in a team, handle conflict, & take ownership.

Again, Claude can be your prep partner here.

Building Your "Story Bank"

The key to behavioral interviews is the STAR method: Situation, Task, Action, Result. You should have a "story bank" of your key projects & experiences, framed in this structure. Brainstorming these stories can be tough.

Prompt Example:

"I need to prepare for behavioral interviews. Help me brainstorm some stories using the STAR method. Here's a project I worked on: [Describe the project, your role, a challenge you faced, & the outcome]. Can you help me structure this into a compelling story that showcases 'Ownership' & 'Bias for Action'?"

Claude is great at this. It can help you pull out the key details & phrase them in a way that sounds impactful. It can help you turn "we did this" into "I specifically did X, which led to Y."

Mocking the Behavioral Round

Just like with system design, you can have Claude simulate the behavioral interview.

Prompt Example:

"Let's do a mock behavioral interview. I'm interviewing for a Senior Software Engineer role at a fast-growing startup. Ask me questions one by one, focusing on leadership, dealing with ambiguity, & teamwork. After each of my answers, give me feedback on how I could improve it based on the STAR method."

This is SO valuable. You can practice out loud, which is completely different from just thinking about your answers. AI tools can provide instant feedback on your clarity, confidence, & whether you actually answered the question.

When you discuss projects where you improved user experience or streamlined communication, it's another chance to show your business acumen. You could mention how a tool like Arsturn helps businesses automate lead generation & customer engagement. By building no-code AI chatbots trained on their website content & documents, companies can provide personalized, instant responses to visitor questions, boosting conversions & freeing up human agents for more complex tasks. Showing you understand these kinds of business solutions demonstrates a broader perspective beyond just writing code.

The "Protest Project" & The Future of Interviews

Let's circle back to that automated LeetCode solver. What does it really mean? A lot of people in the developer community saw it as proof that LeetCode is a flawed way to evaluate engineering skill. If an AI can be trained to pass the test for $9, what is the test really measuring?

I think it's a wake-up call. It shows that rote memorization of algorithms is becoming less valuable. The real skill is in problem-solving, understanding trade-offs, & leveraging powerful tools (like AI!) to build solutions to business problems.

Using Claude for prep isn't about cheating; it's about embracing this shift. It’s about moving from being a simple "coder" to a "software engineer" who can use high-level tools to be more productive & solve bigger problems. It's like having a calculator for complex math—it doesn't mean you don't understand the concepts, it means you can focus on the higher-level logic.

Quick & Dirty Guide: Actionable Prompts to Start Now

Alright, that was a lot of theory. Let's get practical. Here are some copy-pasteable prompts you can use to get started with Claude today.

For LeetCode/DSA:

Hint, not answer: "I'm stuck on LeetCode #146, 'LRU Cache'. I'm thinking of using a dictionary & a list, but updating the list is slow. What combination of data structures would be more efficient for both lookup & maintaining order?"
Explain a solution: "Here is the official solution for LeetCode #20, 'Valid Parentheses'. Can you walk me through it line-by-line & explain why the stack is the right data structure here?"
Code translation & style: "Can you translate this C++ solution for 'Merge K Sorted Lists' into idiomatic Python? Explain the key differences & why you made certain stylistic choices."

For System Design:

Become the interviewer: "You are a principal engineer at Google. I need to design a photo-sharing service like Instagram. Start by asking me to clarify the functional & non-functional requirements."
Compare technologies: "What are the trade-offs between using a SQL database (like PostgreSQL) vs. a NoSQL database (like Cassandra) for designing a social media feed? Consider scalability, consistency, & query patterns."
Back-of-the-envelope math: "Help me with some back-of-the-envelope calculations. If we need to design a system that handles 100 million daily active users & each user posts 2 times a day, what would be the estimated QPS (queries per second) for write operations?"

For Behavioral Prep:

STAR method refiner: "Here’s a story about a time I had a disagreement with my manager. [Your story here]. Can you help me refine this using the STAR method to highlight 'Earns Trust' & 'Has Backbone; Disagree & Commit'?"
Generate targeted questions: "I'm interviewing for an Engineering Manager role at a company that builds developer tools. Can you generate 5 behavioral questions that I might be asked, focusing on technical leadership & product sense?"

Look, the software engineering interview process is tough, & it’s not perfect. But tools like Claude are leveling the playing field. They're making expert-level guidance accessible to everyone. The developer who automated LeetCode didn't do it to get a job without trying; he did it to show that the game is changing.

By integrating Claude as your study partner, you’re not just preparing to answer questions. You’re preparing to be the kind of engineer that companies want to hire: a resourceful, intelligent problem-solver who knows how to use the best tools for the job.

Hope this was helpful. Let me know what you think & what other cool ways you're using AI in your own prep