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40+ Technical Interview Questions Asked at Top Technology Companies

Posted on 
June 19, 2020
|
by 
Team Interview Kickstart

To crack technical interviews at top technology companies, you need to be highly competent in problem-solving, system design, and programming. Companies hiring for technical positions test a candidate’s knowledge of coding, data structures, algorithms, and systems design, in addition to other technical skills relevant to the role.

The most popular technology companies, including Facebook, Apple, Amazon, Netflix, and Google (FAANG), have comprehensive testing processes designed to assess and identify an applicant’s key strengths in various technical areas.

If you’re a programmer with over 10 years of experience, you may have realized that the questions asked in these technical interviews differ from your everyday programming tasks. This is why even the most experienced software developers find it challenging to tackle technical interview questions.

To help you successfully take on tech interview rounds at FAANG and other large tech companies, we have curated a list of over 45 most commonly asked questions. This article walks you through each of the three broad technical interview topic categories:

  • Data Structures
  • Systems Design
  • Coding and Algorithms
  • Bonus Questions (related to your professional work experience)

Kick-start your interview preparation with these technical interview questions. 

So, let’s get started right away! 

Technical Interview Questions on Data Structures

Following some common interview questions on data structures and the answers.

  1. What are the major data structures used in the following – Network Data Model, Hierarchical Data Model, Relational Database Management System?
  • Network Data Model: Graph
  • Hierarchical Data Model: Trees
  • Relational Database Management System: Arrays
  1. What is the minimum number of queues required to implement a priority queue?
    The minimum number of queues required is two — one for storing data and the second one for priorities.
  1. Which data structure is used for recursion?
    The data structure used to achieve recursion is stack. Owing to its Last In First Out (LIFO) attribute, it recollects its caller and returns appropriately when the function has to perform a return. Note that recursive functions can perform iterative or non-recursive functions. When iterative functions are employed, an explicit stack is actively used. 
  1. What are the various methods available to store sequential files?
    There are four methods for storing sequential files:
  • Natural Merging
  • Polyphase Sort
  • Straight Merging
  • Distribution of Initial Runs
  1. Convert the following expression into Prefix and Postfix notations:
    ((A+B))xC – (D-E)^(F+G))
  • Prefix Notation: -*+ABC^ - DE + FG
  • Postfix Notation: AB+ C*DE- FG + ^-
  1. What is the minimum number of nodes that a certain binary tree can possess?
    A binary tree can have a minimum of “0” nodes. This usually occurs when the nodes in question have NULL values.
  1. What is a graph?
    A graph is a common type of data structure that contains within itself a set of ordered pairs. These ordered pairs, commonly referred to as arcs or edges, are primarily used to connect nodes. Nodes are places where data can be stored or retrieved from.
  1. Which data structures are employed in DFS and BFS of a graph?
    Stack is used for DFS of a graph, and queues are used for BFS of a graph.
  1. How do you implement a stack using a queue?
    A stack can be implemented with two queues. If the stack to be implemented is represented as S and the two queues are represented as Q1 and Q2, then S can be implemented in the following two ways:
  • By making the push operation costly: In this method, the oldest element entered is always on top, making the pop operation easy as it pops from the top of the stack.
  • By making the pop operation costly: Here, the most recent element is entered on top of Q1. If Q2 is found to be empty, all the elements are shifted to Q2. The elements are then pushed back to Q1, and the top item from the stack is returned, which is the oldest element. 
  1. What’s the difference between an array and a stack?
    A stack follows the Last In First Out (LIFO) principle, whereas an array doesn’t follow any fixed approach when adding or retrieving data. 

Few More Technical Interview Questions on Data Structures

Here are a few more examples of data-structures-related questions you can expect. Try to answer these:

  1. Explain the features of an AVL Tree.
  2. What are the various types of collision resolution techniques?
  3. Explain the functioning of a recursive algorithm.
  4. Describe the method used in performing a Fibonacci search.
  5. Explain how each sorting technique works and the applications of various sorting techniques.
Related Article: Stay a step ahead in your interview prep! Check out our comprehensive Interview Guides for Microsoft and Netflix.

Technical Interview Questions on System Design 

During tech interviews, you can expect the following types of questions about system design. We’ve included the answers to these.

  1. How do you design a web crawler?
    A web crawler is a program that scans websites for information. This information is useful in creating entries for search engine indexes. While designing web crawlers, dynamic web pages must be prioritized and monitored more often than static pages.  
  1. What is endpoint protection?
    Endpoint protection is a feature in a database that allows you to prevent certain operations from occurring in your system when a set of tasks is complete. Endpoint protection typically protects a system from overloading by reducing its task burden through prioritizing and monitoring.
  1. What are the essential aspects to keep in mind while designing the autocomplete functionality?
  • Provide a typeahead suggestion
  • Ensure your framework supports personalization
  • Calculate the amount of space required for your data
  • Note the queries per second (QPS) handled by your system for better tracking and prioritizing.
  1. Explain the difference between relational and non-relational databases.
  • Relational databases have a pre-set relationship between data stored in the system. Data in relational databases is typically represented in rows and columns.  Most relational databases support a querying language such as MySQL.
  • Non-relational databases have a more flexible structure, and the data is typically represented as key-value pairs. Non-relational databases are important when you need your data to be structured and consistent.
  1. Explain the difference between replication and sharding in database management.
  • Replication is making copies of your existing database. The new databases imitate the properties and features of the existing database. Replication is a process commonly used to manage tasks that require similar prioritizing and execution. If a particular database system collapses, replication ensures redundancy exists so that vital data isn’t lost in transition.
  • Sharding is a technique used to fragment a massive database. Sharding is especially useful when large database systems encounter problems in performing tasks due to their large size. Sharding helps customize your database structure, allowing it to function correctly.  
  1. What are the various types of documentation in systems design?
  • Program documentation
  • System documentation
  • User documentation
  • Operations documentation
  1. Which are the important structure tools employed in systems design?
  • Decision Trees
  • Pseudocode
  • Data dictionary
  • Data flow diagrams

Additional Systems Design Questions to Prepare for Your Next Technical Interview

Now that you know what to expect, take a stab at the following questions:

  1. How would you design a recommendation system?
  2. How do you design a traffic control service?
  3. Design a messenger service like Facebook Messenger. Design a location-based service like Uber.
  4. Explain the requirements of a garbage collection system design.
  5. Explain the method to design a shared drive like Google Drive or Dropbox.
  6. Explain the process and method to design a web crawler.
  7. Explain how to design an API rate limiter.
  8. Design a URL shortener.
Related Article: Did you know that several top companies frequently ask candidates behavioral questions as part of their interview process? Check out these Top Behavioral Questions asked at FAANG companies.

Technical Interview Questions on Coding and Algorithms

These are some of the questions related to coding and algorithms that have been repeatedly asked in technical interviews.

Solving these as a part of your technical interview preparation for FAANG as well as other technology companies will polish your fundamental knowledge about coding and algorithms and give you a solid edge over other candidates.

  1. Given string A — partition A such that each substring is a palindrome.
  2. Given string A and a dictionary (of words) in string B —  demonstrate if string A can be segmented into a space-separated sequence of 1 or more dictionary words.
  3. Return the multiplication of two numbers represented as strings.
  4. Write code in a programming language of your choice to implement your own hash table.
  5. Write a code to demonstrate how to implement three stacks in an array.
  6. For a given binary search tree, find the nth smallest element.
  7. Write a function, Fib(), that takes Integer N and returns the nth Fibonacci number in the sequence.
  8. Can you name a few performance classes that algorithms fall in?
  9. What do you understand by the Big-O notation?

Bonus — Frequently Asked Technical Interview Questions Related to Your Professional Experience

When interviewing at technology companies, interviewers are interested in two major factors:

  • Your subject matter expertise
  • Your professional accomplishments

We’ve already covered technical questions related to the subject matter. Here, we’ve added a set of technical questions about your professional work experience.

  1. What was the last project you worked on? How would you describe your contribution to it? Were there any hurdles, and how were they tackled?
  2. What programming languages do you like working with? And why?
  3. Have you ever reviewed code written by others? What, according to you, are the most critical areas to focus on when reviewing code?
  4. Can you describe your experience while working with agile development methodology?
  5. Are you working on any personal projects? Can you talk about them?
  6. What new and upcoming technologies are you excited about, and why?
  7. Could you walk us through your research process when designing or developing a new software system?

So, this was our list of over 40 interview questions and answers to some of the most common technical interview questions asked during the selection process of large technology companies, including FAANG. 

If you need help with any stage of preparation for your interview with FAANG or other tech giants, you can sign up for our free Webinar. We’ll tell you what it takes to prepare for and nail that tech interview!

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