Most people feel much better when they organize their personal spaces. Whether that’s an office, living room, or bedroom, it feels good to have everything arranged. Besides giving you a sense of peace and satisfaction, a neatly-organized space ensures you can find everything you need with ease.
The same goes for programs. They need data structures, i.e., ways of organizing data to ensure optimized processing, storage, and retrieval. Without data structures, it would be impossible to create efficient, functional programs, meaning the entire computer science field wouldn’t have its foundation.
Not all data structures are created equal. You have primitive and non-primitive structures, with the latter being divided into several subgroups. If you want to be a better programmer and write reliable and efficient codes, you need to understand the key differences between these structures.
In this introduction to data structures, we’ll cover their classifications, characteristics, and applications.
Primitive Data Structures
Let’s start our journey with the simplest data structures. Primitive data structures (simple data types) consist of characters that can’t be divided. They aren’t a collection of data and can store only one type of data, hence their name. Since primitive data structures can be operated (manipulated) directly according to machine instructions, they’re invaluable for the transmission of information between the programmer and the compiler.
There are four basic types of primitive data structures:
- Integers
- Floats
- Characters
- Booleans
Integers
Integers store positive and negative whole numbers (along with the number zero). As the name implies, integer data types use integers (no fractions or decimal points) to store precise information. If a value doesn’t belong to the numerical range integer data types support, the server won’t be able to store it.
The main advantages here are space-saving and simplicity. With these data types, you can perform arithmetic operations and store quantities and counts.
Floats
Floats are the opposite of integers. In this case, you have a “floating” number or a number that isn’t whole. They offer more precision but still have a high speed. Systems that have very small or extremely large numbers use floats.
Characters
Next, you have characters. As you may assume, character data types store characters. The characters can be a string of uppercase and/or lowercase single or multibyte letters, numbers, or other symbols that the code set “approves.”
Booleans
Booleans are the third type of data supported by computer programs (the other two are numbers and letters). In this case, the values are positive/negative or true/false. With this data type, you have a binary, either/or division, so you can use it to represent values as valid or invalid.
Linear Data Structures
Let’s move on to non-primitive data structures. The first on our agenda are linear data structures, i.e., those that feature data elements arranged sequentially. Every single element in these structures is connected to the previous and the following element, thus creating a unique linear arrangement.
Linear data structures have no hierarchy; they consist of a single level, meaning the elements can be retrieved in one run.
We can distinguish several types of linear data structures:
- Arrays
- Linked lists
- Stacks
- Queues
Arrays
Arrays are collections of data elements belonging to the same type. The elements are stored at adjoining locations, and each one can be accessed directly, thanks to the unique index number.
Arrays are the most basic data structures. If you want to conquer the data science field, you should learn the ins and outs of these structures.
They have many applications, from solving matrix problems to CPU scheduling, speech processing, online ticket booking systems, etc.
Linked Lists
Linked lists store elements in a list-like structure. However, the nodes aren’t stored at contiguous locations. Here, every node is connected (linked) to the subsequent node on the list with a link (reference).
One of the best real-life applications of linked lists is multiplayer games, where the lists are used to keep track of each player’s turn. You also use linked lists when viewing images and pressing right or left arrows to go to the next/previous image.
Stacks
The basic principles behind stacks are LIFO (last in, first out) or FILO (first in, last out). These data structures stick to a specific order of operations and entering and retrieving information can be done only from one end. Stacks can be implemented through linked lists or arrays and are parts of many algorithms.
With stacks, you can evaluate and convert arithmetic expressions, check parentheses, process function calls, undo/redo your actions in a word processor, and much more.
Queues
In these linear structures, the principle is FIFO (first in, first out). The data the program stores first will be the first to process. You could say queues work on a first-come, first-served basis. Unlike stacks, queues aren’t limited to entering and retrieving information from only one end. Queues can be implemented through arrays, linked lists, or stacks.
There are three types of queues:
- Simple
- Circular
- Priority
You use these data structures for job scheduling, CPU scheduling, multiple file downloading, and transferring data.
Non-Linear Data Structures
Non-linear and linear data structures are two diametrically opposite concepts. With non-linear structures, you don’t have elements arranged sequentially. This means there isn’t a single sequence that connects all elements. In this case, you have elements that can have multiple paths to each other. As you can imagine, implementing non-linear data structures is no walk in the park. But it’s worth it. These structures allow multi-level storage (hierarchy) and offer incredible memory efficiency.
Here are three types of non-linear data structures we’ll cover:
- Trees
- Graphs
- Hash tables
Trees
Naturally, trees have a tree-like structure. You start at the root node, which is divided into other nodes, and end up with leaf modes. Every node has one “parent” but can have multiple “children,” depending on the structure. All nodes contain some type of data.
Tree structures provide easier access to specific data and guarantee efficiency.
Three structures are often used in game development and indexing databases. You’ll also use them in machine learning, particularly decision analysis.
Graphs
The two most important elements of every graph are vertices (nodes) and edges. A graph is essentially a finite collection of vertices connected by edges. Although they may look simple, graphs can handle the most complex tasks. They’re used in operating systems and the World Wide Web.
You unconsciously use graphs with Google Maps. When you want to know the directions to a specific location, you enter it in the map. At that point, the location becomes the node, and the path that guides you is the edge.
Hash Tables
With hash tables, you store information in an associative manner. Every data value gets its unique index value, meaning you can quickly find exactly what you’re looking for.
This may sound complex, so let’s check out a real-life example. Think of a library with over 30,000 books. Every book gets a number, and the librarian uses this number when trying to locate it or learn more details about it.
That’s exactly how hash tables work. They make the search process and insertion much faster, which is why they have a wide array of applications.
Specialized Data Structures
When data structures can’t be classified as either linear or non-linear, they’re called specialized data structures. These structures have unique applications and principles and are used to represent specialized objects.
Here are three examples of these structures:
- Trie
- Bloom Filter
- Spatial Data
Trie
No, this isn’t a typo. “Trie” is derived from “retrieval,” so you can guess its purpose. A trie stores data which you can represent as graphs. It consists of nodes and edges, and every node contains a character that comes after the word formed by the parent node. This means that a key’s value is carried across the entire trie.
Bloom Filter
A bloom filter is a probabilistic data structure. You use it to analyze a set and investigate the presence of a specific element. In this case, “probabilistic” means that the filter can determine the absence but can result in false positives.
Spatial Data Structures
These structures organize data objects by position. As such, they have a key role in geographic systems, robotics, and computer graphics.
Choosing the Right Data Structure
Data structures can have many benefits, but only if you choose the right type for your needs. Here’s what to consider when selecting a data structure:
- Data size and complexity – Some data structures can’t handle large and/or complex data.
- Access patterns and frequency – Different structures have different ways of accessing data.
- Required data structure operations and their efficiency – Do you want to search, insert, sort, or delete data?
- Memory usage and constraints – Data structures have varying memory usages. Plus, every structure has limitations you’ll need to get acquainted with before selecting it.
Jump on the Data Structure Train
Data structures allow you to organize information and help you store and manage it. The mechanisms behind data structures make handling vast amounts of data much easier. Whether you want to visualize a real-world challenge or use structures in game development, image viewing, or computer sciences, they can be useful in various spheres.
As the data industry is evolving rapidly, if you want to stay in the loop with the latest trends, you need to be persistent and invest in your knowledge continuously.
Related posts
2025 has come to a close, with 2026 already underway. There are many exciting events ahead and future milestones to aim for and look forward to. But it’s also the ideal time to look back over the last 12 months, exploring the most notable achievements we’ve made, lessons we’ve learned, and important moments to reflect on as the new year continues for OPIT’s staff, students, and broader community.
1. Student Commitment
Studying isn’t always easy. It involves long days, and even long evenings sometimes, with a seemingly never-ending series of tasks to accomplish and goals to aim for. It can take a lot out of even the most hard-working and dedicated individuals.
Yet, despite the hardships and challenges, OPIT students demonstrated remarkable resilience, continuous curiosity, and indefatigable determination throughout 2025. Looking back on the year, students at all levels of the OPIT community should feel proud and celebrate their accomplishments.
2. Podcast Launch
2025 saw a lot of new arrivals at OPIT, with fresh projects and innovations arriving on the scene. Chief among them was the OPIT EDGE Podcast, an exciting addition to the institute’s ever-expanding multimedia offerings.
There have already been several episodes of the podcast for students and technology enthusiasts in general to enjoy, with the first episode of this student-driven project involving an in-depth discussion with industry expert Matteo Zangani on the potential of quantum AI technology.
3. Success Stories
While many new students have joined the OPIT ranks in 2025 and will also do so in 2026, others have now achieved their educational objectives and are already moving on to the next exciting steps and chapters in their personal and professional lives.
There are so many inspiring success stories from the last 12 months, it’s impossible to list them all. But just one notable example has to be Maria Brilaki, who recently concluded her Master’s in Responsible AI, defending a powerful thesis related to non-invasive glucose monitoring through near-infrared spectroscopy and machine learning.
4. Graduation in Malta
2025 was a big year of firsts for OPIT, including the institute’s first official graduation ceremony, which took place on March 8 at a grand ceremony in Malta, honoring the achievements of dozens of applied data science and AI graduates.
The hybrid event was open to both in-person and virtual attendees, bringing together members of the OPIT community from across the world. It was a huge moment for the graduates themselves and a thrilling milestone for OPI – a testament to all the hard work that has gone into building this institute.
5. OPIT AI Copilot
Artificial intelligence is the technology of the moment, and OPIT isn’t just dedicated to teaching the next-generation of technology leaders how to work with AI responsibly and efficiently; it’s also interested in harnessing the powers and potential of AI to improve its educational offerings, too.
This culminated in the development and release of OPIT AI Copilot in 2025. This groundbreaking AI tool now provides real-time, personalized learning support, along with contextual assistance, and is available on a round-the-clock basis for students to turn to, as and when they feel the need.
6. Hackathons
2025 also saw OPIT students and faculty take more active roles in various events, including hackathons. In November, for example, OPIT got involved with the 6th edition of the ESCP Hackathon, with several students entering as developers.
This was an exciting and unique opportunity for those students to meet up in person, put the skills they’ve honed during their time at OPIT to the test in a challenging environment, and learn from one another. OPIT will surely participate in more hackathons in the years to come, so stay tuned for more details on upcoming events and how you can play your part.
7. Strengthening Collaboration
From day one, OPIT has focused on building a strong network of established technology and business partners, opening doors and providing opportunities for both education and employment for its students.
This continued throughout 2025, with OPIT strengthening its connections with a number of world-leading organizations, including Accenture, AWS, Hype, Buffetti, and more. Through events like hackathons, career fairs, and more, OPIT makes the most of its ever-expanding and increasingly impressive professional network.
8. Online Career Fair
Another big first for 2025 was the inaugural OPIT Online Career Fair, an event that was held on November 19 and 20, with more than a dozen established and emerging companies from around the world in attendance, including the likes of Deloitte, Tinexta Cyber, Datapizza, RWS Group, Planet Farms, and Nesperia Group.
The only nature of this event ensured that students all enjoyed equal access, no matter where they were based, and everyone was able to hear from industry experts and enjoy the unique array of opportunities on offer, forging their own connections and learning more about brands they might like to work with or for in the future.
9. Education Innovation
OPIT has always been about innovating, delivering newer and smarter ways to learn for students across the globe, no matter their background, budget, or social class. And the institute has continually innovated over the course of 2025, helping students learn skills and broaden their knowledge efficiently and intuitively.
As we enter 2026, OPIT’s innovation is set to be on full display once more, with no less than two new courses for new applicants to choose from: AI-Driven Software Development (Elective) and Business Intelligence and Decision Making (Elective).
10. The Power of the OPIT Community
Perhaps the crowning achievement for OPIT in 2025 was the demonstrable success of not just individual students or faculty members, but the entire OPIT community, as a whole. Everyone, from alumni to new students and seasoned staff members, played their part in the institute’s success, paving the way for more great things and major milestones in 2026 and beyond.
As OPIT Rector and former Italian Minister of Education, Francesco Profumo, puts it:
“What inspires me most is the mindset of our students: forward-looking, responsible, and driven by a desire not just to succeed, but to contribute. Their dedication reminds us why education remains one of the most powerful forces for shaping the future.”
Bring talented tech experts together, set them a challenge, and give them a deadline. Then, let them loose and watch the magic happen. That, in a nutshell, is what hackathons are all about. They’re proven to be among the most productive tech events when it comes to solving problems and accelerating innovation.
What Is a Hackathon?
Put simply, a hackathon is a short-term event – often lasting just a couple of days, or sometimes even only a matter of hours – where tech experts come together to solve a specific problem or come up with ideas based on a central theme or topic. As an example, teams might be tasked with discovering a new way to use AI in marketing or to create an app aimed at improving student life.
The term combines the words “hack” and “marathon,” due to how participants (hackers or programmers) are encouraged to work around-the-clock to create a prototype, proof-of-concept, or new solution. It’s similar to how marathon runners are encouraged to keep running, putting their skills and endurance to the test in a race to the finish line.
The Benefits of Hackathons
Hackathons provide value both for the companies that organize them and the people who take part. Companies can use them to quickly discover new ideas or overcome challenges, for example, while participants can enjoy testing their skills, innovating, networking, and working either alone or as part of a larger team.
Benefits for Companies and Sponsors
Many of the world’s biggest brands have come to rely on hackathons as ways to drive innovation and uncover new products, services, and opportunities. Meta, for example, the brand behind Facebook, has organized dozens of hackathons, some of which have led to the development of well-known Facebook features, like the “Like” button. Here’s how hackathons help companies:
- Accelerate Innovation: In fast-moving fields like technology, companies can’t always afford to spend months or years working on new products or features. They need to be able to solve problems quickly, and hackathons create the necessary conditions to deliver rapid success.
- Employee Development: Leading companies like Meta have started to use annual hackathons as a way to not only test their workforce’s skills but to give employees opportunities to push themselves and broaden their skill sets.
- Internal Networking: Hackathons also double up as networking events. They give employees from different teams, departments, or branches the chance to work with and learn from one another. This, in turn, can promote or reinforce team-oriented work cultures.
- Talent Spotting: Talents sometimes go unnoticed, but hackathons give your workforce’s hidden gems a chance to shine. They’re terrific opportunities to see who your best problem solvers and most creative thinkers at.
- Improving Reputation: Organizing regular hackathons helps set companies apart from their competitors, demonstrating their commitment to innovation and their willingness to embrace new ideas. If you want your brand to seem more forward-thinking and innovative, embracing hackathons is a great way to go about it.
Benefits for Participants
The hackers, developers, students, engineers, and other people who take part in hackathons arguably enjoy even bigger and better benefits than the businesses behind them. These events are often invaluable when it comes to upskilling, networking, and growing, both personally and professionally. Here are some of the main benefits for participants, explained:
- Learning and Improvement: Hackathons are golden opportunities for participants to gain knowledge and skills. They essentially force people to work together, sharing ideas, contributing to the collective, and pushing their own boundaries in pursuit of a common goal.
- Networking: While some hackathons are purely internal, others bring together different teams or groups of people from different schools, businesses, and places around the world. This can be wonderful for forming connections with like-minded individuals.
- Sense of Pride: Everyone feels a sense of pride after accomplishing a project or achieving a goal, but this often comes at the end of weeks or months of effort. With hackathons, participants can enjoy that same satisfying feeling after just a few hours or a couple of days of hard work.
- Testing Oneself: A hackathon is an amazing chance to put one’s skills to the test and see what one is truly capable of when given a set goal to aim for and a deadline to meet. Many participants are surprised to see how well they respond to these conditions.
- Boosting Skills: Hackathons provide the necessary conditions to hone and improve a range of core soft skills, such as teamwork, communication, problem-solving, organization, and punctuality. By the end, participants often emerge with more confidence in their abilities.
Hackathons at OPIT
The Open Institute of Technology (OPIT) understands the unique value of hackathons and has played its part in sponsoring these kinds of events in the past. OPIT was one of the sponsors behind ESCPHackathon 6, for example, which involved 120 students given AI-related tasks, with mentorship and guidance from senior professionals and developers from established brands along the way.
Marco Fediuc, one of the participants, summed up the mood in his comments:
“The hackathon was a truly rewarding experience. I had the pleasure of meeting OPIT classmates and staff and getting to know them better, the chance to collaborate with brilliant minds, and the opportunity to take part in an exciting and fun event.
“Participating turned out to be very useful because I had the chance to work in a fast-paced, competitive environment, and it taught me what it means to stay calm and perform under pressure… To prospective Computer Science students, should a similar opportunity arise, I can clearly say: Don’t underestimate yourselves!”
The new year will also see the arrival of OPIT Hackathon 2026, giving more students the chance to test their skills, broaden their networks, and enjoy the one-of-a-kind experiences that these events never fail to deliver. This event is scheduled to be held February 13-15, 2026, and is open to all OPIT Bachelor’s and Master’s students, along with recent graduates. Interested parties have until February 1 to register.
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