Top Data Structure Interview Questions: For Freshers

Proficiency in Data Structures is a must-have for any well-qualified software developer. Most of the product-based companies search for candidates with a strong understanding of Data Structures, since it is the building block to develop any software. The need for Data Structures is at an all-time high, as it has become inevitable in almost all industries. Hence to ace your interviews easily, you must know these top DSA questions.

For an exploring fresher, we recommend you to have knowledge on the top demand jobs of this decade to make yourself prepared.

What are Data Structures?

There are various types of data such as integer, character, string, boolean, enum and array. The computer interprets a value based on the datatype in which it is stored.

Once the data is stored, we need a way to manipulate it to solve the problems. Data Structures is a format that helps to store and organize data in an efficient way. This helps to increase the overall code performance by establishing relationships among the data sets. Arrays, linked lists, stacks, queues, trees and graphs are some of the data structure types.

Data Structures Interview Questions

Now let us take a look at some of the important data structure questions that will be asked in any interview.

1. List some of the applications of Data Structures

Data structures aid in managing, accessing, and manipulating large amounts of information. In this data-centric world, they are essential in nearly all industries. Some of the key areas where they are utilized include:

  • Blockchain
  • OS Development
  • Database Design
  • Complier Design
  • Machine Learning
  • Financial Systems
  • Image Processing
  • Video Games
  • Web Search Engines
  • Artificial Intelligence

2. How do you categorize linear and non-linear data structures?

In a linear data structure, the data elements are arranged in a sequential manner. One data element will be connected to its previous and/or next element in a linear fashion. There are no multiple relationships between elements and hence the traversal through data can be carried out only in a single run.

Array, queue, linked list and stack are some of the examples of a linear data structure.

Non-linear data structures are the opposite of what we said about linear data structures. The elements are connected in a hierarchical manner and hence their implementation is more complex. There is no memory wastage here.

Graphs and trees are non-linear data structures.

3. What is the difference between file structure and storage structure?

File Structure: A file structure representation is the process of converting data into a form that can be stored in a secondary memory device such as a hard disk or a pen drive. The stored data remains unchanged until it is manually deleted.

Storage Structure: Storage structure stores the data in computer memory that is, RAM. It is not permanent and gets erased as the function that uses this data executes.

4. What are the operations that can be performed on data structure types?

Traversing: Visiting the elements of data structure in a systematic manner.

Searching: Locating the required element in the data structure.

Inserting: Adding an element anywhere inside the data structure. In stack, it is called push and in queue it is called enqueue.

Deleting: Removing an element from the given data structure. In stack, it is called pop and in queue it is called dequeue.

Sorting: Arranging elements of a data structure in ascending or descending order.

Updating: Updating the value or replace an element in a data structure.

5. What is a linked list?

A linked list is a linear data structure in which each element, called a node, contains a reference (or “link”) to the next node in the sequence. The last node in the linked list typically has a link to null, indicating the end of the list.

Linked lists have several advantages over arrays, including dynamic sizing and efficient insertions and deletions. Linked lists can also be easily implemented in a variety of programming languages, making them a common data structure for a wide range of applications.

6. What are the types of linked lists?

Singly Linked Lists – each node contains a reference to the next node

Doubly Linked Lists – each node contains references to both the next and previous nodes.

Circular Linked Lists – the last node contains a reference to the first node

7. How linked lists differ from arrays?

ArrayLinked List
StructureElements are stored in consecutive memory locations.Collection of nodes, where each node contains a reference (or “link”) to the next node in the sequence
Access TimeConstant time complexity of O(1) to access an element.Time complexity of O(n) for searching elements.
SizeHave a fixed size, determined at the time of allocation.Grows dynamically as elements are added or removed.
Insertion/DeletionTime consuming as it requires shifting all the elements after the insertion/deletion point.Average time complexity of O(1) for inserting and deleting elements, as only the links between the nodes need to be updated.
Memory utilizationIneffective as we allocate the size during declarationEffective as the size adapts during runtime

8. When do we use linked list?

We use linked lists when

  • The size of data is not known in advance
  • Faster insertion and deletion are required
  • Less number of random-access operations are involved
  • There is a large number of add or remove operations
  • We have to perform arithmetic operations on long integers
  • We need to manipulate polynomials

9. How do stack and queue work?

A stack is a linear data structure in which elements can be added or removed only from the top. A stack follows the LIFO – Last In First Out principle meaning, the element that was added last is the first to come out.

A queue is a linear data structure in which elements can be inserted only from the rear, and can be removed only from the front. A queue follows the FIFO – First In First Out principle meaning, the element inserted at first is the first to be removed.

10. Where do we see stack and queue in real life?

Stack in real life:

  1. Pile of Books
  2. Women’s Bangles
  3. Floors in a Building
  4. Stack of Plates in a cupboard
  5. Cars parked in a narrow driveway

Queue in real life:

  1. Waiting line
  2. Car wash line
  3. Vehicles in a Traffic Signal
  4. People in an escalator

11. Explain hashmap data structure

A Hash Map (also known as Hash Table) is a data structure that allows you to store key-value pairs and efficiently retrieve the value associated with a given key. A real-world example for hashmap would be when you store your bags in a cloak room and get a token for the spot where you have stored. You will be able to retrieve your baggage only using the token.


There goes the top data structure questions and answers to ace your interview. Sandbox Environments are an ideal place to start practicing what you have learnt. If you are learning on your own, you can use an auto-evaluation supported sandbox like neocoder.

The Great Resignation: How to retain employees

In recent months, there has been a growing trend known as the “Great Resignation” where employees are quitting their jobs in record numbers. This trend is happening across various industries and is creating a significant challenge for employers to retain their best talent. In this blog, we will explore what the Great Resignation is, why it is happening, and what employers can do to retain their best employees.

What is the Great Resignation?

The Great Resignation refers to the wave of employees quitting their jobs and seeking new opportunities. According to a report by Microsoft, more than 40% of the global workforce is considering leaving their current employer this year. This trend is not limited to a specific industry, as employees across various sectors are feeling burnt out and seeking better opportunities.

Why is it happening?

There are several reasons for the Great Resignation. Firstly, the COVID-19 pandemic has changed the way we work, and many employees are looking for more flexibility in their work arrangements. The pandemic has also caused a shift in priorities, with many employees placing a higher value on work-life balance and their mental health.

Secondly, many employees are feeling burnt out due to increased workloads and longer working hours. Remote work has also blurred the line between work and home life, leading to an “always on” mentality that is taking a toll on employees’ well-being.

Thirdly, there is a growing dissatisfaction with compensation and benefits packages. Employees are looking for better pay, improved benefits, and more job security.

What can employers do to retain the best talent?

Retaining top talent is critical for any organization’s success, and employers need to take action to retain their best employees. Here are some strategies employers can use to retain their top talent:

Provide opportunities for growth and development:

Employees are more likely to stay with an employer if they feel there is a path for growth and development within the organization. Employers should invest in their employees’ training and development, offering opportunities for upskilling and career advancement. This can include offering mentorship programs, tuition reimbursement, and leadership training.

Create a positive work environment:

A positive work environment can go a long way in retaining employees. Employers should focus on creating a workplace culture that promotes collaboration, inclusivity, and work-life balance. Offering employee wellness programs and flexible work arrangements can also help create a positive work environment.

Offer competitive compensation and benefits:

Compensation and benefits packages are crucial in retaining top talent. Employers should regularly review and benchmark their compensation packages against industry standards to ensure they are competitive. Employers should also offer attractive benefits packages, such as health insurance, retirement plans, and paid time off. Additionally, employers should consider offering non-traditional benefits such as flexible schedules, telecommuting options, and childcare assistance.

Recognize and reward employees:

Employees who feel recognized and appreciated are more likely to stay with an employer. Employers should regularly recognize and reward employees for their contributions, both formally and informally. This can include bonuses, promotions, and public recognition of their achievements. Employers should also consider offering incentive programs to motivate and retain employees.

Foster open communication:

Effective communication is essential in retaining employees. Employers should foster open communication channels, allowing employees to provide feedback and express their concerns. Employers should also be transparent about company goals, strategies, and decision-making processes. This can include regular town hall meetings, employee surveys, and open-door policies.

Build a diverse and inclusive workplace:

Employees are more likely to stay with an employer that values diversity and inclusivity. Employers should focus on building a diverse and inclusive workplace, ensuring all employees feel valued and respected. This can include offering diversity and inclusion training, creating employee resource groups, and regularly evaluating diversity metrics.


The Great Resignation is a significant challenge for employers, and retaining top talent is critical for any organization’s success. Employers should focus on creating a positive work environment, offering growth opportunities, competitive compensation and benefits, recognizing and rewarding employees, fostering open communication, and building a diverse and inclusive workplace. By taking action to retain their best employees, employers can ensure their organizations continue to thrive in a rapidly changing business landscape.

Download the inclusive L&D framework report to learn more about the personalized training programs you can offer to retain the top talents.

How are Virtual Interviews transforming Hiring Process in today’s Recruitment Landscape? 

Virtual Interviews – The latest hiring trend

The COVID-19 pandemic has caused a huge transformation in all facets of life. From social to work, uncertainty has been an unavoidable element of routine. This uncertainty has had an impact on all industries, and the recruitment and HR industry is no exception. With remote working becoming the new norm, recruiting teams have accepted VIRTUAL HIRING as a new way to recruit, hire, and retain qualified personnel. Organizations have rapidly adopted virtual hiring, which replaces the conventional hiring process. 

With the constant transitions in the recruitment industry, it’s no doubt that virtual interviews are the way of the future. They provide several advantages, such as reducing no-shows, providing flexibility, enhancing safety, saving resources, broadening the talent pool, assessing applicants’ technical abilities, and so much more. With all these benefits, it is no surprise that virtual interviews are becoming increasingly popular among employers and job seekers. Get ready to dive deep and unravel the significant benefits of virtual interviews. 

Listing out the Top Six Benefits of Virtual Interviews 

Greater candidate pool: Virtual hiring allows companies to reach a much larger pool of potential candidates, regardless of location. Recruiters are no longer limited to the confines of one region when seeking the ideal employee. With the fading of geographical limitations and the increasing adoption of virtual hiring, recruiters can now look to a wider field of talent and bring the right person to the organization, no matter where they are. This not only broadens the range of individuals available but also provides the opportunity to cultivate a more diverse and multicultural workforce. 

Saves recruiters’ time: Virtual hiring can save recruiters time in several ways. One way is by allowing them to conduct initial screenings and interviews remotely, which eliminates the need for in-person meetings. This can save time in terms of both scheduling and travel. Additionally, virtual hiring platforms often include tools for scheduling, tracking, and managing candidate communications, which can streamline the recruitment process and reduce the time recruiters need to spend on administrative tasks. Additionally, it also allows reaching a larger pool of candidates and the ability to automate repetitive tasks, allowing recruiters to focus on more critical tasks such as identifying top talent. 

Cost savings: Several companies today are decreasing their recruitment and hiring activities during this time, but that may change as the economy improves in the future. Virtual hiring can make it easier and more cost-effective to accommodate hiring highs and lows. Utilizing scheduling and assessment software is much more affordable than hiring additional members for the talent acquisition team. Virtual hiring eliminates the need for expensive recruiting trips and on-site interviews, saving companies on travel and lodging expenses, which can add up quickly.  

Increased flexibility: Virtual interviews also allow for greater flexibility in the interview process itself. Candidates can take the interview from a location of their choice, and employers can include a wider range of team members in the interview process. This allows for a more thorough evaluation of the candidate and can increase the chances of finding the best fit for the company. Virtual hiring enables easier communication between parties, as they can use video conferencing and instant messaging tools to communicate in real-time. Virtual hiring can save time by allowing companies to conduct interviews, assessments, and reference checks simultaneously, speeding up the hiring process. 

Unbiased hiring: Organizations can diminish the possibility of conscious and unintentional biases in the recruitment process by using virtual hiring tools. AI-tools-powered hiring techniques can be programmed to disregard demographic specifics, including race, gender, and age. Another advantage of virtual interviews is their ability to create a more level playing field for candidates. In-person interviews can be affected by a candidate’s appearance, physical presence, or other diverse factors. Virtual interviews remove these factors, allowing the interviewer to focus on the candidate’s skills and qualifications. This can help to reduce unconscious bias and create a more diverse and inclusive hiring process. 

Better candidate experience: Virtual hiring can make the application and interview process more comfortable and less stressful for candidates, resulting in a better candidate experience overall. This can help attract top talent and improve the company’s reputation as an employer. 

Final thoughts: 

In conclusion, virtual interviews have transformed the hiring process by increasing convenience, creating a more level playing field for candidates, and allowing for greater flexibility in the interview process. While there are challenges to virtual interviews, companies can take steps to overcome them and ensure a successful hiring process. As technology advances, virtual interviews will likely become even more prevalent in the hiring process. Hence, companies must embrace this new way of conducting interviews to have a competitive edge in finding the best candidates for their organization. 

Marketing cheat sheet for organizing Hackathon

Promoting hackathons is a crucial element that should be a priority for every organization, but it often receives less attention. To get a good outreach, a dedicated marketing team takes complete responsibility for formulating strategies to reach as many people as possible, focusing on the right audience for the event. In this read, we’ll look into some proven strategies that can be implemented in your next hackathon event,

Strategizing Hackathon through Marketing

  • Dedicated Marketing Team – When it comes to promotion, there are broader audiences, but it’s also essential to identify the right set of audiences. A dedicated team that exclusively focuses on strategizing and planning the promotional campaign should be deployed. To ensure the intended adverts reach the right people, the marketing team takes complete responsibility for formulating strategies to get as many people as possible, focusing on the right audience for the event.
  • Tailored content and design team – Every organization has unique requirements, and a team committed to making tailored content should be deployed to support this. Also, the design team helps you create content that suits your organization in designing the posters and catchy phrases for promotion for the event. 
  • Social Media Campaigns – In today’s digital era, you can’t imagine a promotional campaign without social media being a part of it. Uninterrupted social media campaigns (LinkedIn, Instagram, Facebook etc.) are to run across various platforms to foster engagement and enhance outreach. Different ads are promoted based on user behaviour by identifying where your targeted community hangs out.
  • Targeting colleges and Universities – Considering that targeted audiences are from colleges, it would be outright to promote the event in the right colleges to reach out to a more significant number of audiences. With intended audiences primarily being students, tools like neohire assist you in reaching out to universities directly through their campus connections and help you reach over 2000+ colleges across India. 

The significance of Dashboard in Hackathons

Dashboards are essential for analyzing critical metrics while monitoring performance in real time. This offers a visual representation of a metric’s in-depth progress and growth over time. With Dashboards, you have complete visibility into the event at every stage, allowing you to track progress in real-time. Here are a few dashboards that e

Registration Dashboard

To get a complete picture of the registration progress, it’s essential to use a dashboard to track and fully control the registration flow in real time. The Registration dashboard offers a graphical view of the registered candidates used to view the key metrics and track areas that need improvement. Some of the metrics that can be tracked using this dashboard are

  • Total Registrations
  • Geographical area
  • Colleges reached
  • Degree wise

Live Dashboards for coding contests

An efficient way of presenting data that is easy to track the candidate’s performance in real-time is live dashboards, providing admin with critical data. It offers a variety of individual-specific insights that are not limited to attendance, performance, and participation. You have complete authority over the candidate’s test, varying from video proctoring to terminating the test.


Although there are numerous methods to promote a hackathon event, these are some of the effective techniques that have been proven to attract a larger audience and actively engage with them. If you’re looking to promote or host your hackathon, Neohire can assist you to do it on its feature-rich platform.