Leantaas Software Engineer Interview Questions + Guide in 2025

Leantaas is a technology company dedicated to transforming healthcare operations through innovative software solutions.

As a Software Engineer at Leantaas, you will be responsible for developing and deploying software products, primarily focusing on web backend services and data pipeline management. This role requires proficiency in various programming languages and frameworks, alongside a strong foundation in data structures, algorithms, and system design. You will work closely with cross-functional teams to understand project requirements and deliver scalable solutions. Experience with database design and SQL, as well as familiarity with tools like Apache Airflow for data processing, are critical to success in this position.

The ideal candidate should embody Leantaas' commitment to innovation and collaboration, demonstrating strong problem-solving skills and the ability to adapt to new technologies. A Masters in Computer Science or a related field is preferred, although relevant experience may also be considered.

This guide will help you prepare for your interview by equipping you with insights into the role, the skills required, and the types of questions you might encounter during the interview process.

The interview process for a Software Engineer at LeanTaaS is structured and consists of multiple stages designed to assess both technical skills and cultural fit.

1. Initial Phone Screen

The process begins with a technical phone screen, typically lasting around 30 minutes. During this call, the recruiter will review your resume and ask questions related to your experience and skills. You can expect to tackle a medium-level data structures question, which will help gauge your problem-solving abilities and technical knowledge.

2. Onsite Interviews

Following the initial screen, candidates are invited for an onsite interview, which usually consists of four rounds, each lasting approximately 45 minutes.

• Round 1: Data Structures and Problem Solving
  In this round, you will be presented with a medium-level data structures question. This is designed to evaluate your understanding of algorithms and your ability to solve problems efficiently.

• Round 2: SQL Database Design
  Here, you will be tasked with a scenario, such as designing a database schema for a movie and genres application. You will need to demonstrate your knowledge of data normalization, data consistency, and write basic SQL queries involving operations like GROUP BY and JOIN.

• Round 3: System Design
  This round focuses on your ability to design systems. You will be asked a general system design question that assesses your understanding of architecture and scalability.

• Round 4: Hiring Manager Interview
  The final round typically involves a behavioral interview with the hiring manager. Expect questions that explore your past experiences, teamwork, and how you align with the company culture. You may also encounter a coding problem, such as the Merge Time Intervals challenge.

Throughout the interview process, candidates should be prepared to discuss their previous projects and experiences in detail, as well as demonstrate their technical skills through practical coding exercises.

Next, let's delve into the specific interview questions that candidates have encountered during this process.

In this section, we’ll review the various interview questions that might be asked during a Software Engineer interview at LeanTaaS. The interview process will assess your technical skills, problem-solving abilities, and your fit within the company culture. Be prepared to demonstrate your knowledge in data structures, SQL, system design, and behavioral aspects.

Data Structures and Algorithms

1. Can you explain the difference between a stack and a queue?

Understanding fundamental data structures is crucial for this role, as they are often used in various algorithms.

How to Answer

Discuss the definitions of both data structures, their use cases, and how they differ in terms of data access.

Example

“A stack is a Last In First Out (LIFO) structure, where the last element added is the first to be removed. A queue, on the other hand, is a First In First Out (FIFO) structure, where the first element added is the first to be removed. Stacks are often used in scenarios like function call management, while queues are used in scheduling tasks.”

2. Describe a time you optimized an algorithm. What was the problem and the solution?

This question assesses your practical experience with algorithms and your ability to improve efficiency.

How to Answer

Provide a specific example, detailing the problem, the original algorithm, and how you optimized it.

Example

“I was tasked with sorting a large dataset. Initially, I used a bubble sort algorithm, which was inefficient for the size. I researched and implemented a quicksort algorithm, reducing the time complexity from O(n^2) to O(n log n), which significantly improved performance.”

3. How would you approach solving a problem that requires merging overlapping intervals?

This question tests your problem-solving skills and understanding of algorithms.

How to Answer

Outline your thought process, including how you would represent the intervals and the steps to merge them.

Example

“I would first sort the intervals based on their start times. Then, I would iterate through the sorted list, comparing the current interval with the last merged interval. If they overlap, I would merge them by updating the end time of the last merged interval. If not, I would add the current interval to the merged list.”

4. What is the time complexity of your favorite sorting algorithm?

This question evaluates your understanding of algorithm efficiency.

How to Answer

Discuss your favorite sorting algorithm, its time complexity in different scenarios, and why you prefer it.

Example

“My favorite sorting algorithm is quicksort. Its average time complexity is O(n log n), but in the worst case, it can degrade to O(n^2). However, with good pivot selection, it performs efficiently on average, making it suitable for large datasets.”

SQL and Database Design

1. How would you design a database schema for a movie rental system?

This question assesses your database design skills and understanding of normalization.

How to Answer

Discuss the entities involved, their relationships, and how you would ensure data integrity.

Example

“I would create tables for Movies, Customers, and Rentals. The Movies table would include attributes like title, genre, and release year. The Customers table would have customer details, and the Rentals table would link customers to the movies they rented, including rental dates. I would ensure normalization by avoiding data redundancy and maintaining referential integrity.”

2. Write a SQL query to find the top 5 most rented movies.

This question tests your SQL querying skills.

How to Answer

Provide a clear SQL query and explain your thought process.

Example

“SELECT movie_id, COUNT(*) as rental_count FROM Rentals GROUP BY movie_id ORDER BY rental_count DESC LIMIT 5; This query counts the number of rentals for each movie and orders them in descending order to get the top 5.”

3. What is the difference between INNER JOIN and LEFT JOIN?

This question evaluates your understanding of SQL joins.

How to Answer

Explain the definitions and use cases for both types of joins.

Example

“An INNER JOIN returns only the rows that have matching values in both tables, while a LEFT JOIN returns all rows from the left table and the matched rows from the right table. If there is no match, NULL values are returned for columns from the right table.”

4. How do you ensure data consistency in a database?

This question assesses your knowledge of database integrity and consistency.

How to Answer

Discuss the methods you would use to maintain data consistency.

Example

“I would implement transactions to ensure that a series of operations either complete successfully or roll back to maintain consistency. Additionally, I would use constraints like foreign keys and unique indexes to enforce data integrity.”

System Design

1. Design a URL shortening service. What components would you include?

This question tests your system design skills and ability to think through architecture.

How to Answer

Outline the components of the system, including how you would handle scalability and data storage.

Example

“I would include components like a web server to handle requests, a database to store the original URLs and their shortened versions, and a hashing function to generate unique keys. For scalability, I would consider using a distributed database and caching frequently accessed URLs.”

2. How would you design a system to handle real-time notifications?

This question evaluates your ability to design systems that require real-time processing.

How to Answer

Discuss the architecture, including message queues and how you would ensure reliability.

Example

“I would use a publish-subscribe model with a message broker like RabbitMQ or Kafka to handle notifications. Subscribers would listen for events and process them in real-time. To ensure reliability, I would implement retries and dead-letter queues for failed messages.”

3. What considerations would you take into account when designing a microservices architecture?

This question assesses your understanding of microservices and their challenges.

How to Answer

Discuss the benefits and challenges of microservices, including communication and data management.

Example

“I would consider service independence, scalability, and fault tolerance. Each service should have its own database to avoid tight coupling. I would also implement API gateways for communication and monitoring to ensure that services are functioning correctly.”

4. Describe how you would handle data migration in a large-scale application.

This question tests your knowledge of data management during system changes.

How to Answer

Outline the steps you would take to ensure a smooth migration process.

Example

“I would first create a detailed migration plan, including a backup of the existing data. I would then perform the migration in stages, testing each stage for data integrity. Finally, I would monitor the application post-migration to address any issues that arise.”

Behavioral Questions

1. Describe a challenging project you worked on. What was your role?

This question assesses your teamwork and problem-solving skills.

How to Answer

Provide a specific example, detailing your contributions and the outcome.

Example

“I worked on a project to develop a new feature for our application under a tight deadline. I took the lead in coordinating with the design and backend teams, ensuring that we met our milestones. The feature was successfully launched on time and received positive feedback from users.”

2. How do you prioritize tasks when working on multiple projects?

This question evaluates your time management and organizational skills.

How to Answer

Discuss your approach to prioritization and how you manage competing deadlines.

Example

“I use a combination of urgency and importance to prioritize tasks. I maintain a task list and regularly review it to adjust priorities based on project needs. This approach helps me stay focused and ensures that I meet deadlines effectively.”

3. How do you handle conflicts within a team?

This question assesses your interpersonal skills and ability to work collaboratively.

How to Answer

Discuss your approach to conflict resolution and maintaining a positive team dynamic.

Example

“When conflicts arise, I believe in addressing them directly and openly. I encourage team members to express their viewpoints and facilitate a discussion to find common ground. This approach often leads to a better understanding and a collaborative solution.”

4. What motivates you to perform well in your job?

This question evaluates your intrinsic motivation and alignment with the company’s values.

How to Answer

Discuss what drives you professionally and how it aligns with the company’s mission.

Example

“I am motivated by the opportunity to solve complex problems and make a meaningful impact through my work. I find fulfillment in collaborating with others to create innovative solutions that improve user experiences, which aligns with LeanTaaS’s mission to enhance healthcare efficiency.”