If you’ve been preparing for a data engineering job at companies like Meta, Amazon, Apple, Netflix, or Google—often called MAANG—you might have noticed something surprising. They don’t just ask questions about tools like SQL, Python, or cloud platforms. They also ask about data structures and algorithms!

This might seem confusing at first. After all, as a data engineer, your job is to work with data pipelines, ETL processes, and databases, right? So, why do you need to know data structures and algorithms (DSA)?

In this blog, we’ll break down why MAANG companies ask these questions and why they are important for data engineers.

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What Are Data Structures and Algorithms?

Before we get into the reasons, let’s quickly explain what data structures and algorithms are, in simple terms:

Data Structures:

These are ways to organize and store data so that it can be used efficiently. Some examples are:

• Arrays: Like a list of items.

• Hash Tables: Like a dictionary where you can quickly look up a value by a key (like a phone book where you look up numbers by name).

• Trees and Graphs: More complex structures that represent relationships between data, like a family tree.

Algorithms:

These are step-by-step methods for solving problems or performing tasks, like:

• Sorting: Putting a list of numbers in order.

• Searching: Finding a specific item in a list.

• Pathfinding: Figuring out the shortest route between two points.

Now, let’s see why MAANG companies focus on these topics in data engineering interviews.

1. They Test Your Problem-Solving Skills

At its core, a data engineer’s job is to solve problems. Whether it’s building a data pipeline or optimizing how data is processed, you’re constantly working on finding efficient solutions.

When MAANG companies ask questions about data structures and algorithms, they want to see how you approach problems. These questions help them understand:

• How you break down a problem.

• How you think about different solutions.

• How efficient your solution is (in terms of speed and memory usage).

For example, if they ask you to sort a list of data, they want to see if you can choose the best algorithm for the job, and explain why you chose it.

2. They Want to See If You Can Write Efficient Code

Data engineers at MAANG companies deal with huge amounts of data. We’re talking about millions or even billions of records. When you’re handling that much data, writing efficient code becomes very important.

Let’s say you’re asked to write a program that searches through a large dataset. If you don’t use the right data structure (like a hash table or a binary search tree), the program could take too long to run or use too much memory.

By testing your knowledge of DSA, MAANG companies want to see if you can:

• Optimize your code to run fast, even when dealing with large datasets.

• Use the right tools (data structures and algorithms) to get the job done efficiently.

3. It Shows You Can Work with Scalable Systems

MAANG companies work at a massive scale. Think about all the data Google, Amazon, or Facebook has to process every second—whether it’s user data, search queries, or transaction records.

To handle such a large scale, systems need to be scalable—meaning they can grow and handle more data without slowing down. This is where data structures and algorithms come in.

For example, if you know how to use a distributed algorithm to process data across multiple machines, you can make sure the system keeps running efficiently as more data is added. MAANG companies want to make sure that the data engineers they hire understand how to build scalable systems and work with large datasets efficiently.

4. They Want to Test Your Technical Depth

MAANG companies are known for having high technical standards. When they ask about data structures and algorithms, they’re looking to see if you have a strong technical foundation.

Even though data engineers don’t work with algorithms every single day, understanding DSA shows that you:

• Know how computers work under the hood.

• Can think logically and systematically.

• Have a strong understanding of computer science fundamentals, which will help you tackle any technical challenge that comes your way.

In other words, these questions show that you’re not just someone who knows a few tools; you’re someone who understands how to solve complex problems in an optimal way.

5. It's a Standardized Way to Compare Candidates

Finally, MAANG companies use data structures and algorithms questions because they provide a standard way to compare candidates.

When they ask every candidate the same types of questions, it’s easier to see how each person performs. For example:

• Who came up with the most efficient solution?

• Who was able to explain their thought process clearly?

• Who knew how to optimize their code?

This makes the interview process more fair and helps companies find the best problem-solvers.

Conclusion

So, why do MAANG companies ask data structures and algorithms questions in interviews for data engineers? Here’s a quick recap:

• They test your problem-solving skills.

• They see if you can write efficient code that handles large amounts of data.

• They check if you can build scalable systems for massive amounts of data.

• They want to ensure you have technical depth and a solid understanding of computer science fundamentals.

• They use it as a standardized way to compare candidates.

Even though data structures and algorithms might not seem directly related to your day-to-day tasks as a data engineer, they are essential for showing that you can solve problems, write efficient code, and work with large-scale systems. By practicing DSA, you’re not just preparing for interviews—you’re becoming a better data engineer!

So, while it might feel challenging at first, understanding these concepts will help you in your job and make you stand out during the interview process.

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Resources used to write this blog:

• Learn from YouTube Channels

• I used Google to research and resolve my doubts

• From my Experience

• I used Grammarly to check my grammar and use the right words.