Coding Interview Prep in 2024

Did you know that over 60% of software engineers find coding interviews to be the most challenging part of landing a job in tech?

Getting a job at a FAANG company like Meta, Amazon, Apple, Netflix, or Google, has always been competitive, but as of 2024, these companies are raising the bar even higher making the process even more challenging.

Economic uncertainty and layoffs, increased competition, specialized skills, and higher standards and expectations, have led to a more selective hiring process at these tech giants.

On the other hand, when you start the preparation, you face issues in finding the right resources. Although platforms like LeetCode have thousands of coding questions available, you might just wonder where to start, what to focus on, and how to effectively build the skills that top tech companies are looking for.

That’s where you need a targeted and strategic approach to save time and increase your chances of success.

We at design gurus have empowered hundreds of thousands—including future FAANG engineers— with the coding expertise and design skills needed to excel in these interviews. Whether you're tackling complex algorithms or understanding common coding patterns, our platform provides everything you need to stand out.

In this blog, we’re going to walk you through what you need to know for coding interview prep in 2024 and how you should prepare.

Let’s get started!

Step 1. Understanding the Coding Interview Structure

Interviews have evolved quite a bit over the years, especially with the rise of remote work and the fast-paced changes in the tech industry.

Every top tech company requires proper interview preparation.

If you’re getting ready for one, it’s important to know what to expect and how to prepare.

Typically, the interview process has several stages:

1. Initial Screening

This is usually the first step where a recruiter or a hiring manager has a quick conversation with you to understand your background and see if you’re a good fit for the role.

What to Expect: It’s usually a phone or video call. You might be asked about your resume, your past projects, and your basic understanding of coding concepts.

2. Technical Phone Screen

When you reach the second stage, you’ll likely face a live coding challenge which has become the main part of technical interviews, especially for software engineering roles.

The idea is simple: you’re given a problem to solve while the interviewer watches you code in real-time.

These technical interviews aren’t just about getting the right answer; it’s about how you approach the problem, how you think, and how you handle pressure.

3. Online Assessment or Virtual Interview

An online assessment is a timed, remote test that evaluates your coding abilities, problem-solving skills, and sometimes your knowledge of specific programming languages or technologies. These assessments are usually conducted through platforms like HackerRank, Codility, or CoderPad.

4. Onsite Interviews

This is the core of the coding interview process and usually involves several rounds of interviews with different members of the team.

What to Expect:

• Coding Problems: Similar to the technical phone screen but more in-depth. You might get several problems that test your understanding of data structures and algorithms.

• System Design Interviews: You may be asked to design a scalable system from scratch. This tests your ability to architect complex software solutions, considering trade-offs, scalability, and performance. Learn about the main concepts with our System Design Interview Roadmap.

• Behavioral Interviews: These focus on how you work with others, handle challenges, and fit within the company culture. You’ll be asked about past experiences and how you handled specific situations. Ace your behavioral interview with our Grokking the Modern Behavioral Interview course.

• Take-home Projects: These are typically assigned in scenarios where the company wants to evaluate a candidate's ability to work on a more complex problem or project that cannot be easily assessed in a short interview session. The goal is to see how a candidate approaches real-world tasks, such as designing a system, developing a feature, or solving a problem that requires deeper thought and more time.

Section 2. Step-by-Step Coding Interview Prep

When it comes to coding interviews, LeetCode is the go-to platform for preparation.

Although it offers thousands of problems, it lacks organization which can make the whole preparation process overwhelming.

You might just wonder how many questions you need to solve to feel truly prepared and memorizing answers to all these coding questions is not feasible.

Practical interview preparation requires understanding the underlying concepts, practicing with real-world examples, and learning how to communicate your thought process effectively—just like Google engineers do.

But how can you do that?—this is what we are going to cover next.

Here's a step-by-step guide to help you get ready:

1. Master the Fundamentals

Start by revisiting the basics.

Knowing how to efficiently implement a data structure can help you solve just any coding problem. Therefore, focus on understanding common data structures like:

• Arrays
• Linked lists
• Stacks
• Queues
• Trees
• Graphs

Make sure you know how to implement these structures and how to use them to solve coding questions.

Also, practice coding algorithms related to these data structures to strengthen your foundation with our dedicated course on Data Structures and Algorithms and the Art of Recursion.

2. Solve LeetCode Questions

LeetCode is one of the most popular platforms for practicing coding interview skills. Many candidates turn to it because the LeetCode questions are similar to those asked by tech companies.

Begin with easy problems and gradually move to more challenging ones. Try to focus on identifying the key question pattern in each problem, which will help you recognize similar problems in real interviews.

Check out our courses on Dynamic Programming, Coding Question Patterns, and Grokking75 to solve the top 75 questions.

3. Understand Algorithms and Their Applications

Beyond data structures, you need to be familiar with a range of algorithms.

This includes sorting algorithms, searching algorithms, dynamic programming, and more advanced topics like multithreading, and graph algorithms.

Knowing how to apply these algorithms to solve problems is crucial, especially when dealing with complex data structures.

If you are searching for an expert guide, join our courses on multithreading and graph algorithms.

4. Practice with Sample Solutions

As you solve coding questions, it's helpful to review sample solutions. This will not only help you understand different approaches but also show you how to reach an optimal solution.

Don’t just memorize answers, though—focus on understanding the process behind them. This will prepare you to handle variations of the same problems during your actual interview.

5. Mock Coding Interviews

Mock coding interviews are an essential part of your preparation. They simulate the real interview environment, helping you practice your coding interview skills under pressure.

We offer opportunities at design gurus to participate in mock interviews with industry professionals and ex-FAANG engineers at DesignGurus.io. These sessions help you identify areas where you need improvement and get comfortable with the interview format.

6. Review and Reflect

After each practice session, take the time to review what you did. Look at the coding questions you struggled with and understand why.

Were you missing some fundamental knowledge? Did you fail to ask clarifying questions?

Use this reflection to guide your next steps in your preparation.

Stage 3. Main Topics to Master for a Coding Interview

When preparing for a coding interview, certain key topics are essential to focus on.

These are the building blocks of technical interviews, and a strong grasp of them will greatly improve your chances of success.

Here’s a breakdown of the most important concepts you should be ready to tackle for a technical interview.

1. Data Structures

Data structures are the backbone of computer science, and they are heavily tested in a coding interview.

You should be comfortable with the following:

• Arrays and Strings: Understand how to manipulate arrays and strings, perform operations like searching, sorting, and merging, and solve problems involving them.

• Linked Lists: Know how to implement and work with singly and doubly linked lists, and be prepared to solve problems like reversing a list, detecting cycles, and merging lists.

• Stacks and Queues: Be familiar with these linear data structures, understand their operations (push, pop, enqueue, dequeue), and solve problems like balancing parentheses or evaluating expressions.

• Trees and Graphs: Learn about binary trees, binary search trees, AVL trees, and basic graph algorithms like BFS (Breadth-First Search) and DFS (Depth-First Search). Practice problems related to traversals, finding the height, lowest common ancestor, and graph connectivity.

• Hash Tables: Understand how hash tables work, including concepts like collision resolution. Be prepared to use them for problems involving counting frequencies, finding duplicates, and implementing caches.

Check out our comprehensive courses on Basic Data Structures and Graph Algorithms for coding interviews.

2. Algorithms

Algorithms are at the heart of problem-solving in a coding interview.

Here are the key ones to master when you start preparing:

• Sorting and Searching: Understand popular sorting algorithms like Quick Sort, Merge Sort, and Heap Sort, as well as binary search. Be able to discuss their time and space complexity.

• Dynamic Programming: It is a technique used to solve problems by breaking them down into simpler subproblems. Common problems include the knapsack problem, longest common subsequence, and coin change problem.

• Recursion and Backtracking: Many problems can be solved recursively or using backtracking. Get comfortable with recursive problem-solving and understand how to optimize recursive solutions using techniques like memoization.

• Greedy Algorithms: Greedy algorithms make locally optimal choices at each step with the hope of finding the global optimum. Examples include Dijkstra’s algorithm for shortest paths and the coin change problem.

If you are facing a technical question on algorithms or recursion, remember that approaching them from a questions pattern perspective can help you recognize the common themes that top tech companies frequently test.

For an extensive understanding of these concepts, check out our courses on Dynamic Programming and Recursion for coding interview.

3. Problem-Solving Strategies

Beyond specific topics, being able to approach problems effectively is crucial for interview preparation:

• Understanding the Problem: Always start by fully understanding the problem statement. Don’t rush into coding; take time to think about what’s being asked.

• Breaking Down Problems: Learn to break problems down into smaller, manageable parts. This can make complex problems easier to solve and reduce the chances of getting stuck.

• Optimizing Solutions: Once you have a working solution, think about how you can make it more efficient. This might involve improving the algorithm’s time complexity or reducing its memory usage.

Stage 4. How to Practice Coding Interview Problems

Here’s a step-by-step guide to help you effectively practice and improve your coding skills for interview preparation.

1. Start with the Basics

Before getting into complex problems, ensure you have a solid understanding of the basics, such as arrays, stacks, queues, and common algorithms like sorting and searching.

2. Use Online Platforms

• Practice Daily: Consistency is key. Set aside time each day to solve at least one problem. Platforms like DesignGurus, LeetCode, and HackerRank are excellent for solving practice questions. Start with easy problems and gradually move to more difficult ones as you build confidence.

• Timed Practice: Many coding interviews are timed, so it’s important to practice algorithm questions under similar conditions. Use a timer to simulate the pressure of an actual interview, which will help you manage your time effectively during the real thing.

• Topic-Wise Practice: Focus on one topic at a time (e.g., arrays, hash table, graph theory, optimization problems). This approach helps you build a deep understanding of each area before moving on to the next.

3. Learn by Example

• Study Solutions: After solving a problem, compare your solution with others. Many platforms have discussions where people share different approaches. This can provide insights into more efficient or elegant ways to solve the problem.

• Revisit Problems: If you struggle with a problem, don’t just move on. Revisit it after a few days to reinforce what you’ve learned. This repetition helps solidify your understanding.

Stage 5. Which Programming Language to Use for Coding Interviews

The tech industry in 2024 is diverse, with companies using a variety of programming languages depending on their products, services, and technological needs.

For example, Python has seen a surge in popularity due to its simplicity and its wide use in fields like data science, machine learning, and web development.

On the other hand, languages like Java and C++ remain staples in backend development, finance, and performance-critical applications.

Choosing the right programming language for coding interviews is an important decision for software engineers.

The language you choose should be one you’re comfortable with and can use efficiently under pressure.

When deciding which language to use in a coding interview, it’s important to consider where the industry is headed and what specific skills companies are looking for.

Here are some practical considerations:

1. Industry Relevance

Look at the job you’re applying for and the technologies that the company is using.

For instance, if you’re aiming for a position in a company known for its AI projects, Python might be the best choice due to its extensive libraries and ease of use in prototyping.

If you’re applying for a role in a financial institution, Java or C++ could be more relevant due to their performance capabilities and use in legacy systems.

2. Your Comfort Level

The most important factor is how comfortable you are with a language.

Interviews are stressful enough without the added pressure of wrestling with a language you’re not confident in.

If you’ve been coding in Python for years and know its quirks, it’s probably the best language for you. Similarly, if you’ve been working in Java or C++ and are familiar with their environments, stick with what you know.

3. Versatility

Some languages are more versatile across different types of problems.

Python, for example, is known for its readability and efficiency, making it a strong choice for a wide range of problems from algorithms to data manipulation.

Java, while more verbose, offers strong type-checking and object-oriented features that can help structure your solutions better in system design questions.

4. Interviewer’s Expectations

It’s also worth considering what the interviewer might expect.

In many cases, Python is a safe bet because it’s widely understood and accepted across various tech roles.

However, if you’re interviewing for a specialized role, such as low-level systems development, the interviewer might expect you to use C++ or a similar language that gives you fine control over system resources.

The language you choose should be one you’re comfortable with and can use efficiently under pressure.

The most commonly recommended languages for coding interviews are Python and Java.

Python

Python is known for its simplicity and readability. Its extensive standard library can help you avoid reinventing the wheel.

For instance, Python provides built-in functions for sorting, string manipulation, and working with data structures like dictionaries and sets.

Also, its syntax is straightforward, which allows you to write code quickly and with fewer lines.

Python’s standard library is also extensive, offering a wide range of built-in functions that can save you time during an interview.

When to Use It: Python is especially good for beginners or those who want to focus more on problem-solving rather than syntax.

It’s also widely accepted by interviewers across the tech industry.

Polish your basics in more detail with our dedicated course on Python Fundamentals.

Java

Java is a robust, object-oriented language that’s widely used in enterprise environments. It’s known for its performance and reliability.

Java forces you to think about things like memory management and types, which can be beneficial if you’re applying for a role where these concepts are important.

When to Use It: If you’re interviewing for a role in a company that heavily uses Java, or if you’re already proficient in it, this could be a good choice for algorithm problems.

Besides these factors, some companies have preferences for certain languages. Therefore, it’s worth checking the job description or reaching out to recruiters to see if there’s a preferred language for the role you’re applying for.

Stage 6. How Long Should You Practice for Coding Interviews

There’s no one-size-fits-all answer to how long you should practice algorithm questions for coding interviews.

The amount of time you should dedicate to coding interview practice depends on your current skill level, the complexity of the role you're aiming for, and how much time you can realistically commit.

Here’s a general guide to help you plan your coding interview prep.

1. Beginners (3-6 Months)

If you’re new to coding or haven’t practiced coding problems in a while, you should give yourself 3 to 6 months to prepare.

This timeframe allows you to:

• Learn the Basics: Spend the first month or two getting comfortable with the basics of your chosen programming language and understanding fundamental data structures and algorithms.

• Daily Practice: As you progress, practice selected questions daily starting with easier problems, gradually moving to more challenging ones as you build confidence.

• Mock Interviews: In the last 1-2 months, start doing mock coding interviews to simulate real conditions and refine your problem-solving approach.

2. Intermediate Level (2-3 Months)

If you have some experience and are familiar with basic algorithms and data structures, 2 to 3 months of focused preparation might be enough.

• Focused Practice: Spend the first-month revisiting core topics like arrays, lists, trees, and basic algorithms.

• Advanced Problems: Use the next month to tackle more complex problems, including dynamic programming, graph theory, and system design (if relevant).

• Mock Interviews: As you get closer to the interview date, incorporate regular mock interviews to test your readiness under timed conditions.

3. Experienced Candidates (1-2 Months)

If you’re an experienced developer, 1 to 2 months might suffice, especially if you regularly engage with coding challenges.

• Refresher: Spend the first few weeks reviewing key concepts and solving problems you might not have encountered recently.

• Focus on Weak Areas: Identify and work on any areas where you feel less confident, whether it’s a particular data structure, algorithm, or type of problem.

• Mock Interviews: Simulate interviews with peers or use platforms like DesignGurus.io to polish your skills.

Check out the complete roadmap to clearing technical interviews in 2024.

4. Daily Commitment

Regardless of your experience level, try to dedicate 1 to 2 hours daily to coding practice. This consistent effort helps solidify your understanding and keeps your problem-solving abilities sharp.

5. Final Push Before the Interview

In the final two weeks leading up to the interview, increase your practice intensity. Focus on solving timed problems and doing mock interviews to simulate the real interview experience.

Also, review common coding interview questions or recommended practice questions related to the specific company or role you're applying for.

Stage 7. Top Coding Interview Questions

When preparing for a coding interview, it’s essential to practice selected questions that are commonly asked at top tech companies and help build your problem-solving skills.

We have listed five top questions for software engineers to guide interview preparation at a tech company.

Data Structures and Algorithms

Data structures and algorithms-based questions are the main focus of a coding interview, focusing on your ability to manipulate data efficiently and solve algorithmic problems.

By mastering various data structure techniques, you can significantly improve your problem-solving skills and tackle coding challenges with confidence.

If you have a limited time, try to practice the recommended practice questions.

Here are the important technical interview questions that you must prepare:

1. Number of Islands (Solution)
   Given a 2D array (i.e., a matrix) containing only 1s (land) and 0s (water), count the number of islands in it.

2. Reverse a Linked List (Solution)

Reverse a singly linked list.

3. Merge Two Sorted Lists (Solution)

Given two sorted linked lists, merge them into a single sorted list.

4. Find the Lowest Common Ancestor (LCA) of a Binary Search Tree (Solution)

Given a binary search tree (BST), find the LCA of two given nodes.

5. Maximum Subarray (Solution)

Find the maximum sum of any contiguous subarray of size 'k'.

By focusing on the data structure questions from a pattern perspective, you’ll be able to see the connections between different problems and approach them with confidence.

Stage 8. Remote Interview Best Practices

With the rise of remote work, many IT companies now conduct coding interviews online. While the core of the interview remains the same, there are some additional considerations to keep in mind for remote interviews.

1. Set Up Your Environment

Ensure your workspace is quiet, well-lit, and free from distractions. Companies expect you to be as professional in a remote interview as you would be in person. Make sure your internet connection is stable, and test your setup beforehand—this includes your microphone, camera, and any screen-sharing tools you'll be using.

2. Practice Coding with Standard Library Functions

In a remote interview, efficiency is key. Familiarize yourself with the standard library functions in your chosen programming language, as these can save you time during the interview. Knowing how to quickly implement a function using these built-in tools shows your practical understanding of the language.

3. Communicate Your Thought Process

One challenge in remote interviews is ensuring that the interviewer understands your approach to solving the problem. As you work through algorithm questions, be sure to explain your approach thoroughly. This helps the interviewer follow your logic and gives you a chance to showcase your problem-solving skills and understanding of the questions pattern perspective.

4. Ask Clarifying Questions

Without the benefit of face-to-face interaction, it’s even more important to ask clarifying questions to ensure you fully understand the problem. This can prevent misunderstandings and demonstrates that you’re thorough in your approach.

5. Prepare for Technical Questions

During remote interviews, tech companies may use shared coding platforms like CoderPad or HackerRank. Make sure you’re comfortable with these tools and know how to navigate them. Practicing on these platforms will help you manage the technical aspects of the interview, allowing you to focus on solving the problems.

6. Focus on Optimal Solutions

Even in a remote setting, the goal is to find the most efficient solution to the problem. Don’t rush to memorize answers, but instead, aim to understand how to derive an optimal solution. This shows that you can handle both the coding aspect and the efficiency of your solution, which is critical in real-world scenarios.

How Are Candidates Assessed in Technical Interviews

Tech companies have specific criteria to shortlist candidates.

Although the priorities and standards can vary for different companies, the main evaluation criteria are based on a similar set of skills.

Here are the general assessment criteria that companies use for candidates:

1. Communication Skills: How clearly you explain your strategy and solutions during the interview.

2. Problem-Solving Capabilities: How effectively you approach and break down complex coding challenges.

3. Debugging: Your ability to identify and fix errors in your code and ensure it handles all edge cases.

4. Technical Expertise: Your knowledge of programming languages, algorithms, and data structures, and how well you apply them to solve problems.

Frequently Asked Questions

1. How can I best prepare for a coding interview if I have limited time?

Focus on practicing the most common coding problems related to data structures and algorithms. Prioritize quality over quantity by deeply understanding the solutions to a few key problems rather than skimming many. Also, review key concepts and language-specific details that are relevant to the role.

2. What should I bring to a coding interview?

Bring multiple copies of your resume, a notepad, a pen, and any necessary identification. If the interview involves an online coding test, bring a fully charged laptop or tablet.

3. How do I quickly determine the time complexity of my code during an interview?

To quickly determine the time complexity, focus on the most time-consuming operations, like loops and recursive calls. Count how many times each operation runs relative to the input size (n). In the case of nested loops, multiply their complexities, but if it is recursive algorithms, identify the recurrence relation then solve.

4. What kind of questions should I ask the interviewer?

Ask about the team's culture, typical work processes, opportunities for growth, and the technologies used in the role. You can also inquire about how success is measured in the position or what challenges the team is currently facing.

5. Should I use pseudocode or actual code during a whiteboard interview?

It's generally better to use actual code during a whiteboard interview as it demonstrates your ability to implement your logic in a real programming environment. However, you can start with pseudocode to outline your approach if it helps clarify your thoughts.

6. How important is it to know the specific syntax of a programming language for the interview?

Knowing the syntax is important, but interviewers are usually more focused on your problem-solving capabilities. Small syntax errors are typically not a dealbreaker as long as your logic is sound and you can explain your approach clearly.

7. What are some common mistakes to avoid during a coding interview?

Avoid rushing into coding without first planning your approach. Don’t ignore edge cases, and ensure you test your solution with different inputs. Also, avoid being overly confident or dismissive of alternative solutions.

8. How should I dress for the technical interview?

Dress in business casual attire unless you have specific information about the company's culture suggesting otherwise. Tech companies often have a more relaxed dress code, but it's better to be slightly overdressed than underdressed. For example, a collared shirt with slacks or a blouse with a skirt/pants is usually appropriate.

9. How long does it take to hear back after a coding interview?

It typically takes one to two weeks to hear back after a coding interview. If you haven't heard anything after two weeks, it's okay to send a polite follow-up email to check on the status of your application.

Final Words

Technical interview preparation in 2024 is not just about practicing endless problems anymore—it’s about practicing smart. And this is where most candidates struggle.

If you are going through the same phase, jumping to different platforms, and working exhaustively on countless problems, this guide is your savior.

Simply, revise your basic concepts, focus on identifying the key question patterns, and just practice your coding muscles regularly.

With our interview prep resources at DesignGurus.io, you can understand the intricacies of the interviews, hone in on what matters most, and adopt the right approach to easily pursuing your dream job at top tech companies.

Good luck and keep coding!