Deloitte Software Engineer Interview Questions + Guide in 2024

Deloitte is a high-profile “Big Four” accounting and “professional services” organization known for providing audit, consulting, risk advisory, tax, and legal services. With a diverse client base across industries and around the world, Deloitte relies on its Software Engineers to deliver a wide range of services to clients, maintain internal systems, and stay competitive in a technology-driven business environment.

A career as a Software Engineer at Deloitte comes with numerous benefits, including involvement in impactful projects across sectors, opportunities for professional development, and connections within a worldwide network.

This guide provides a detailed overview of the Deloitte interview process. It includes commonly asked Deloitte software engineer interview questions and practical tips to enhance your chances of securing the position.

Deloitte’s interview process usually consists of four main interview rounds but may differ based on the team and seniority of the position.

1. Application

You can apply for jobs through their website, recruiters, or trusted online platforms. You can consider asking for an employee referral through your network when you apply as well. Take some extra time to check that your resume highlights projects that are relevant to the role, focusing on quantifying the success of key projects, as well as some of your soft skills. These are both qualities that Deloitte looks for in promising candidates.

2. Recruiter Screening

In this first step of the selection process, a recruiter assesses your background, experience, and fit for the role. Make sure to use this opportunity to ask the recruiter questions to understand the position and prepare some canned responses to advocate for yourself as a strong candidate.

3. Online Technical Assessment

This round may be conducted through platforms like HackerEarth. You will be given a timed test (1.5 hours) to complete problems related to algorithms, data structures, and coding in a language of your choice. Python is a popular choice for coding problems.

4. Video Interview(s)

If it is a good fit, you will be invited to meet a partner and/or a senior manager over a video call, although in some cases, you may be asked to visit on-site. There are usually three or four rounds of these discussions, involving a mix of technical, behavioral, and situational interview questions.

Interview tips from Deloitte’s careers page:

1. We’re impressed when candidates have taken the time to do some research and learn about us.
2. Recent trends have dictated business casual attire, but it’s still appropriate to wear a business suit.
3. When you want to learn more about who we are and what we do, it lets us know you’re interested.
4. Specific examples of how you’ve contributed to an organization or learned something exciting are of interest to us.

Software Engineers should expect a wide range of questions during their interview at Deloitte, particularly in the realm of SQL, Python programming, cloud computing, and data structures & algorithms. Apart from technical questions, you can expect a few behavioral questions designed to assess how well you will handle client interaction and a collaborative, dynamic work culture.

1. Can you describe a time when you had to explain a complex technical problem to a client who wasn’t from a technical background?

As a Deloitte Software Engineer, you may have to work in client-facing roles and convey complex technical concepts to non-technical stakeholders.

How to Answer

Focus on a specific instance where you broke down a technical issue for a non-technical audience. Use the STAR method of storytelling - discuss the Specific situation you were challenged with, the Task you decided on, the Action you took, and the Result of your efforts.

Example

“In my previous role, I was once tasked with explaining a complex cloud integration issue to a client unfamiliar with cloud computing. I likened the process to merging different departments within a company, each with its unique processes and data. I made sure to use minimal technical jargon. This helped the client grasp the challenges of the problem.”

2. Why do you want to join Deloitte?

Interviewers will want to know why you specifically chose the Software Engineer role at Deloitte. They want to establish if you’re passionate about the company’s culture and values, or if your interest is much more opportunistic.

How to Answer

Your answer should reflect knowledge of Deloitte’s work, culture, and the specific opportunities that attract you to the company. It’s important to be honest and specific about how Deloitte’s offerings align with your career goals.

Example

“I am eager to join Deloitte because of its reputation for fostering a culture of continuous learning and innovation. I’m particularly attracted to the opportunity to work on diverse and challenging projects across various industries, which aligns perfectly with my goal of developing a versatile skill set in Software Engineering. Additionally, Deloitte’s commitment to social impact resonates with my values, and I am excited to contribute to projects that have a meaningful impact on society.”

3. Tell us about a time when you had to manage a particularly demanding project. How did you handle the stress and ensure timely delivery?

This question aims to evaluate your project management skills and resilience under pressure, which are essential qualities for handling fast-paced projects at Deloitte.

How to Answer

Focus on a challenging project you’ve worked on, and share specific actions you took to meet deadlines, like proactive issue resolution or efficient workload delegation. Specifying these strategies shows that you can think under pressure and delegate duties when needed.

Example

“During a critical project at my last job, where we had a tight deadline and high client expectations, I organized regular team check-ins to prioritize tasks. I encouraged open communication and scheduled brief decompression periods for the team at the end of each sprint. This planned approach helped us deliver the project two days ahead of schedule.”

4. What are your three biggest strengths and weaknesses?

Deloitte values continuous learning and improvement. Demonstrating self-awareness is essential to succeed in their company culture.

How to Answer

Focus on job-relevant strengths: highlight technical skills, problem-solving, or teamwork aligned with the position. Acknowledge weaknesses objectively and frame areas for improvement in a growth-focused way. Briefly mention how you’re addressing your weaknesses - this shows the interviewer that you are a proactive person.

Example

“My top strengths are strong problem-solving through efficient code analysis and collaborative teamwork. In terms of areas for improvement, I’m currently honing my public speaking skills for more impactful presentations and will continue to practice through internal workshops.”

5. Describe a time when you had to learn a new technology or language quickly for a project. How did you approach the learning process, and what impact did this have on the project?

This question seeks to assess your adaptability, which is crucial in a fast-paced environment like Deloitte, where you may have to frequently upskill with new projects.

How to Answer

When responding to this question, follow the STAR method: Situation, Task, Action, and Result, emphasizing your strategy and discussing the result.

Example

“For a project that required Python, a language I was less familiar with, I leveraged online resources and set up a practical, project-based learning schedule. This approach enabled me to contribute to my project within two weeks. This proactive approach helped the team meet project milestones and even incorporate advanced Python features ahead of schedule.”

6. You are about to get on a plane to Seattle and want to know if you should bring an umbrella. You call 3 of your friends (selected randomly) who live there and ask them one by one if it’s raining. Each friend has a 2⁄3 chance of telling you the truth and a 1⁄3 chance of messing with you and lying. All 3 friends tell you that it’s raining. What is the probability that it is indeed raining in Seattle?

This question tests your knowledge of Bayesian probability. Engineers at Deloitte may need to make data-driven predictions relying on interpreting incomplete data.

How to Answer 

Explain Bayes’ Theorem and outline how you would calculate the probability on that basis.

Example

“Solving with Bayes’ theorem, and assuming that there is a 50% chance of precipitation in Seattle, there’s an 89% chance (or P(Raining) = ⁸⁄₉) that it is actually raining.”

7. Write a Python function to parse a log file and extract error messages along with their timestamps. How would you optimize it for large files?

It’s important in Software Engineering roles to know how to handle and process data, particularly large files.

How to Answer

Explain your approach logically, focusing on the use of efficient data processing techniques. Highlight how you would optimize your method for handling large files.

Example

“I’d use a combination of regular expressions to identify error patterns and a line-by-line file reading approach to manage memory efficiently. For large files, I’d implement a buffered reading strategy to process the file in chunks, thereby minimizing memory usage and ensuring the application remains responsive even with complex log files.”

8. Write a query that, for each page, gets the percentage of the users who recommended that they are in the same postal code as the location associated with that page.

This question tests your SQL querying and your ability to handle complex aggregations, skills that are essential for backend development tasks in Deloitte’s projects.

How to Answer

Describe the logical steps of your query, including joining the necessary tables, filtering the data based on postal code, and calculating the percentage using SQL aggregation functions.

Example

“I’d write a query to join the pages table with the user recommendations table, using a WHERE clause to filter users in the same postal code as the page. Then, I’d use COUNT and GROUP BY functions to calculate the total number of recommendations per page and divide this by the total number of users in the same postal code, multiplying by 100 to get the percentage.”

9. Compare quicksort, merge sort, and heap sort. In what scenarios would you prefer one algorithm over the others?

You will need to have a thorough knowledge of sorting algorithms in various scenarios, particularly for high-load, data-intensive projects.

How to Answer

Your answer should include a brief comparison of the three algorithms focusing on time and space complexities. Then, you should discuss the scenarios in which each algorithm would be most effective, discussing factors like dataset size, memory constraints, and the need for stability in sorting. Contextualize your answer by discussing a practical example.

Example

“Quick sort is generally fast with an average and best-case complexity of $O(n \log n)$, but its worst-case complexity is $O(n^2)$, which can be a concern with poorly chosen pivots. However, its in-place sorting makes it memory efficient.

Merge sort, on the other hand, always has a time complexity of $O(n \log n)$, making it predictable and stable, but it requires additional space, which is $O(n)$. This makes it less memory efficient compared to quick sort but a reliable choice for large datasets.

Heap sort also offers $O(n \log n)$ complexity and does not require additional space, making it a good option when memory usage is a concern. However, it is typically slower in practice than the other two due to more overhead in heap operations.

In a high-load system, where efficiency and quick response times are crucial, I would prefer quick sort for medium-sized datasets due to its in-place sorting and performance. For larger datasets, especially where stability is a concern (like sorting orders where stability can maintain the order of similar elements), merge sort would be preferable despite its higher space requirement. Heap sort could be an option when memory is a constraint, but the dataset isn’t excessively large to avoid the overhead of heap operations.”

10. Given a list of integers, identify all the duplicate values in the list. Assume that the list can contain both positive and negative numbers, and the order of the list does not matter.

Understanding data structures well is key to efficiently wrangling data in software development scenarios.

How to Answer

Outline an efficient method, possibly using a data structure like a set for tracking seen elements while maintaining optimal time complexity.

Example

“I would iterate through the list, using a set to keep track of unique numbers. As I encounter numbers, I’d check if they are already in the set. If it is, it’s a duplicate, and I would add it to the list of duplicates; if not, I’d add it to the set. This approach ensures O(n) time complexity, making it efficient even for large lists.”

11. What would be the functional and non-functional requirements if you were tasked with designing a video conferencing application like Zoom?

The interviewer wishes to evaluate your systems design skills, particularly in understanding the comprehensive requirements necessary for designing robust, user-friendly, and efficient software systems like a video-conferencing application.

How to Answer

Approach the answer by considering the key components and characteristics a video conferencing system must have (functional) and the quality attributes it must adhere to (non-functional).

Example

“First and foremost, the application should support real-time video and audio streaming, have a scalable architecture to manage multiple simultaneous video conferences, and include features for screen sharing, chat functionality, user authentication, and data storage for meeting recordings and scheduling.

Importantly, the system must be designed for high reliability and availability, ensuring minimal downtime. It should offer low latency video streaming, be scalable to accommodate peak loads and ensure secure data transmission and storage to protect user privacy. Additionally, it should be optimized for various platforms and network conditions, maintaining a balance between video quality and bandwidth usage.”

12. Write a SQL query to select the 2nd highest salary in the engineering department.

You will need to demonstrate your understanding of window functions in solving specific data retrieval problems, as such operations are necessary for the day-to-day coding requirements for a Software Engineer at Deloitte.

How to Answer

Choose the function that best fits the requirement of the query. In this case, DENSE_RANK or RANK would be appropriate, as they can handle ties in salary values. Explain how you would use the chosen function in a subquery to achieve the desired result.

Example

“I would use the DENSE_RANK function. This function will assign ranks to salaries within the department while handling ties appropriately. I would create a subquery that assigns a rank to each salary using DENSE_RANK, ordered in descending order, and then in the outer query, I would select the salary where the rank is 2. This approach ensures that if multiple employees share the highest salary, the query will still return the true 2nd highest salary.”

13. Can you explain the concept of cohesion in software design? Also, how would you approach optimizing the latency of a high-traffic web application?

The concept of cohesion is needed to design maintainable and modular software, which is essential for large-scale and complex projects common at Deloitte.

How to Answer

Outline strategies that demonstrate your experience in performance tuning and system scalability.

Example

“Cohesion refers to the degree to which elements of a module in software design belong together. High cohesion means that the module’s components are closely related and focused on a single task, leading to more maintainable and reliable software. It’s about ensuring that each module has a specific, well-defined purpose. To optimize latency in a high-traffic application, I’d focus on efficient load balancing, implementing a Content Delivery Network (CDN) for static assets, optimizing databases for faster queries, and using caching strategies effectively. It’s also vital to minimize the use of blocking operations and to optimize both client-side and server-side code.”

14. Given a 2-D matrix P of predicted values and actual values, write a function to calculate precision and recall metrics.

Understanding precision and recall is valuable in data science projects, especially for predictive modeling problems.

How to Answer

Briefly explain the concepts of precision and recall, and then describe how you would implement a function to calculate these metrics, given a confusion matrix.

Example

“Given a 2-D matrix with predicted and actual values, we can calculate these by first determining the counts of true positives (TP), false positives (FP), and false negatives (FN). The function would iterate over the 2-D matrix to count TPs, FPs, and FNs. Precision is then TP/(TP+FP), and Recall is TP/(TP+FN). These calculations provide insight into the model’s performance, especially in scenarios where class imbalance is a concern.”

15. Can you write a recursive function using pointers to reverse a linked list?

Knowledge of data structures, recursion, and pointers is crucial in Software Engineering roles to tackle complex projects such as developing a system for a client to analyze large streams of transactional data.

How to Answer

Describe the general logic of using recursion and pointers to reverse a linked list. Focus on the mechanism of changing the node links through recursive calls and pointer manipulations.

Example

“I would create a function to traverse the list until it reaches the last node. At each recursive call, the function would manipulate the next pointer of the current node to point to its previous node, effectively reversing the link. The recursion stops when it reaches the end of the list, and the last node becomes the new head of the list.”

16. Write a Python function to return the maximum profit you can achieve by buying and selling a stock.

Understanding how to maximize profit in a given scenario using algorithmic thinking is key in many software engineering tasks, including financial analysis and data processing.

How to Answer

Explain the logic behind your approach, discussing how you track the maximum profit at each stage (after each buy and sell) and how the problem resembles optimizing decisions in a changing environment. Briefly mention the importance of efficient and scalable code.

Example

“In this function, I will use dynamic programming to keep track of the profits after each buy and sell action. The function iterates through each price, updating the potential profits. This approach ensures that we consider the best possible outcome at each stage, which is crucial for optimizing profits in a dynamic setting like stock trading or managing real-time data.”

17. Which data structures can be used for implementing LRU cache?

This question gauges your practical understanding of data structures, specifically in designing efficient algorithms for caching mechanisms.

How to Answer

Focus on why your selections are appropriate choices in terms of access time, order maintenance, and ease of deletion and insertion.

Example

”The most efficient way to implement an LRU cache is by using a combination of a hash map and a doubly linked list. The hash map provides O(1) access time to cache items, and the doubly linked list maintains the order of items based on their usage, with the least recently used items towards the front. This combination allows quick access, addition, and removal of items, which is essential for the performance of an LRU cache.”

18. Given a list of sorted integer lists, write a function to create a combined list while maintaining sorted order without importing any libraries or using sort functions in Python.

Software Engineers need to understand concepts like merging sorted integer lists for applications like streamlining logistics and scheduling tasks.

How to Answer

Go through a step-by-step approach to merge the lists while maintaining sorted order. Focus on how you iterate through each list, compare elements, and choose the smallest element at each step to add to the final merged list. Highlight the efficiency of your approach.

Example

“In my solution, I’ll maintain an array of pointers to track the current element in each list. At each step, I’d look for the smallest element in each list and add it to the merged list. This way, we effectively merge all lists while maintaining their sorted order. This approach is efficient because it can minimize comparisons and eliminate the need for any external sorting library. Each iteration involves only a comparison of the heads of the remaining lists.”

19. Explain the Round Robin scheduling algorithm and how it differs from the other scheduling algorithms.

This knowledge is particularly relevant in environments where software solutions require efficient resource management.

How to Answer

Provide a concise explanation of the Round Robin algorithm, emphasizing its fairness and time-sharing, and then briefly compare it with other common scheduling algorithms in terms of their approach to task prioritization and resource allocation.

Example

“The Round Robin scheduling algorithm assigns a fixed time quantum to each process in a queue and processes them in a cyclic order. When a process’s time quantum expires, it is moved to the back of the queue, and the next process is serviced. This differs from algorithms like First-Come, First-Served, which execute processes in the order they arrive without time slicing, or Priority Scheduling, which prioritizes tasks based on their priority level rather than treating all processes equally. Round Robin is particularly noted for its fairness and prevention of process starvation, but it can lead to higher context switching overhead.”

20. You are generating a yearly report for your company’s revenue sources. Calculate the percentage of all total revenue made to date that was made during the first and last years recorded in the table.

This question assesses your ability to query financial data, a common task in many consulting and audit projects at Deloitte.

How to Answer

Describe a method to extract the revenue from the first and last years in the data set and then calculate their combined percentage contribution to the total revenue. Emphasize accuracy and efficiency in data handling.

Example

“I’d first identify the first and last years in the revenue data set. Then, I would sum up the total revenue for these two years and divide it by the total revenue made to date, finally multiplying by 100 to get the percentage.”

21. You have been tasked with designing three classes: text_editor, moving_text_editor, and smart_text_editor.

The interviewer wishes to evaluate your coding and object-oriented programming skills, particularly in implementing class hierarchies, method overriding, and maintaining state across multiple class instances.

How to Answer

Approach the answer by considering the functionalities and behaviors each class should have (functional) and the inheritance and state management each class must maintain (non-functional).

Example

“First, create the base class text_editor with methods to write, delete, and perform a special operation on the text. The write_line method appends a given string to the existing text, while the delete_line method removes a specified number of characters from the end of the text.

Next, extend the text_editor class to create the moving_text_editor class. Override the special_operation method to toggle the cursor between the beginning and the end of the text, allowing new text to be appended at either position based on the cursor’s state.

Finally, extend the text_editor class to create the smart_text_editor class. Implement an undo functionality in the special_operation method, which allows undoing any number of previous operations by maintaining a history of text states.”

22. Write a query to determine the top 5 actions performed during the week of Thanksgiving, and rank them based on number of times performed.

Understanding how to query and rank data based on specific criteria is crucial in many data analysis tasks, including determining the most frequent user actions within a specified timeframe.

How to Answer

Explain the logic behind your SQL query, discussing how you filter the data for the given date range, group the results by the action performed, and rank the actions based on their frequency. Highlight the importance of using functions like dense_rank() to handle ties in ranking and ensuring the results are ordered correctly.

Example

“In this query, I use a WHERE clause to filter events that occurred during the week of Thanksgiving (11/22/2020 - 11/28/2020). By grouping the results by action and counting the occurrences of each action, I can determine the frequency of each action performed. The dense_rank() function is then used to assign ranks to these actions based on their counts, ensuring that actions with the same count receive the same rank. The LIMIT clause is used to retrieve the top 5 actions. This method ensures that we accurately capture and rank the most frequent actions during the specified period.”

Here are some tips to help you excel in your interview:

Research Deloitte and Its Projects

Understand Deloitte’s business model, the types of clients they work with, and the kinds of software engineering projects they handle. Familiarize yourself with their culture, values, and any recent news or big projects.

You can also read Interview Query members’ experiences on our discussion board; although we do not have any Deloitte interview discussions yet, you can find plenty of insider tips for Software Engineering roles at similar firms.

Explore the specific role through our Learning Paths to gain a comprehensive understanding of how your skills align with the requirements of this position.

Visit Deloitte’s career page to understand what they look for in potential candidates.

Brush Up on Technical Skills

Revisit algorithms (graphs, trees, and sorts), data structures, system design principles, and coding practices. Practice writing efficient, clean, and well-documented code. Be prepared for coding challenges in Python and SQL.

Check out our guide specifically for SQL and Python interview questions, or practice some cool engineering projects to bolster your resume.

Prepare Behavioral Interview Answers

Deloitte values soft skills. Be ready to discuss your experiences with teamwork, communication, handling deadlines, and client interactions.

To test your current preparedness for the interview process, try a mock interview to improve your communication skills.

Understand Data Security and Compliance

At Deloitte, you will be expected to handle sensitive data. Depending on the exact role, you may have to know about data governance, privacy laws (like GDPR), and methods to secure data, such as encryption and access controls. Check the job description document to ensure that you’re covering all your bases.

What is the average salary for a Software Engineering role at Deloitte?

The average base salary for a Software Engineer at Deloitte is $101,010, making the remuneration competitive for prospective applicants.

For more insights into the salary range of Software Engineers at various companies, check out our comprehensive Software Engineer Salary Guide.

Where can I read more discussion posts on the Deloitte Software Engineer role here in Interview Query?

Here is our discussion board where Interview Query members talk about their interview experiences, although we do not have any posts specifically on the Deloitte experience yet. You can use the search bar and filter for Software Engineering posts.

Are there job postings for Deloitte Software Engineer roles on Interview Query?

We have jobs listed for Software Engineer roles at Deloitte, which you can apply for directly through our job portal. You can also have a look at similar roles that are relevant to your career goals and skill set by filtering by location, company, and position.

Succeeding in a Deloitte Software Engineer interview questions requires solid technical skills as well as the ability to demonstrate your collaborative and critical thinking persona.

If you’re considering opportunities at other companies, check out our Company Interview Guides. We cover a range of similar companies, so if you are looking for Software Engineer positions in the other Big 4 firms, you can check our guides for PWC, EY, KPMG, and more.

For other data-related roles at Deloitte, consider exploring our Data Engineer, Business Analyst, Data Scientist, and similar guides in our main Deloitte Interview Guide.

With a solid interview strategy and our data-backed tips, you can confidently approach the interview to showcase your potential as a valuable employee to Deloitte. Check out more of our content here at Interview Query, and we hope you’ll land your dream role very soon!