7 Websites to Practice Data Structure & Algorithm Coding Challenges

Software engineering interviews often involve several rounds. Data structures and algorithms are one of the critical areas that employers may test. As such, it’s a no-brainer that you need to sharpen your data structures and algorithms (DSA) skills if you want to ace technical interviews.

Fortunately, there are many websites you can use to learn about DSA and practice your understanding.

These are some of the best platforms for practicing your knowledge of data structures and algorithms through coding challenges. These websites support various programming languages, so whichever you’re familiar with, you’re good to go.

LeetCode is one of the best platforms to prepare for technical interviews. It’s packed with a variety of problems that you can solve, touching on different areas including common to advanced data structures and algorithms.

If you’re starting your journey, you can use the platform’s crash course to learn about the basics and gain the confidence and skills to start solving problems. The platform also provides editorial solutions to problems, showcasing the best approach for when you’re stuck.

You can also view solutions from other LeetCode users. For advanced users, LeetCode has regular weekly and bi-weekly contests where you can compete with others to solve problems, gain points, and climb the ranks.

HackerRank is another solid platform for practicing your DSA skills. It includes a variety of topics and languages but, most importantly, dedicated sections for data structures and algorithm problems. Like LeetCode, you can sort the coding challenges by difficulty level (Easy, Medium, and Hard).

You can also sort questions by their subdomains, like search, arrays, trees, heaps, sorting, graph theory, dynamic programming, and recursion. The site covers all the data structures every developer should be familiar with.

Under each question, there’s an editorial section with answers, another for discussions, where you can seek clarification and help from your peers, and a leaderboard.

Preparing for an upcoming technical interview? If so, you can make use of HackerRank Kits that let you practice specific DSA skills. HackerRank also has contests, but they are less frequent than LeetCode’s.

Codewars is not as streamlined as the first two websites. Its challenges might seem a bit random, but you can use its filters to only display challenges related to DSA. You can view data structures by selecting the Data Structures tag and algorithms by selecting the identically named tag.

You can sort the challenges by difficulty level using Codewars’ Japanese martial arts-inspired system (the lower the number, the harder the problem). Don’t let the ranking system confuse you, though. The most important point is polishing your DSA skills by solving challenges on the platform.

Codility is a platform that is dedicated to helping companies hire software developers. Still, in addition to that, it also offers a section for training. The app has various lessons but is very limited relative to the first three sites in this list. Codility divides its training into three categories: challenges, lessons, and exercises.

You can jump in and take on any problem, but what makes Codility unique is that it gives you a timeframe to find your solution. Other platforms just track the time you take to solve a problem, except for contests and challenges.

This is particularly important if you have an interview soon because it ensures that, as much as you are practicing your problem-solving skills, you’re sharpening your time-management skills at the same time.

HackerEarth has several sections, including a practice tab that covers data structures, algorithms, interview preparation, mathematics, basic programming, and more. The algorithm section comprises nearly a thousand problems, while the algorithms section has over 350 problems. After signing up, you need to select the languages you use. Still, you can use any language to solve the challenges.

The platform also has an editorial section under each problem, which showcases the solution and the thought process behind it. You can practice further questions under the specific subdomain by checking for similar problems.

Like HackerRank and LeetCode, the Discussions tab is where you can chat with other students about the challenges you’re facing while tackling a problem. HackerEarth also includes regular challenges and a leaderboard if you’re the competitive type.

Techie Delight has nearly 600 problems on its platform. Unlike most of the professional sites in this list, this one’s free, and you don’t have to create an account to practice. When you visit the site, the first problem is waiting for you to solve. We recommend using the filters available to make good use of the site. Use the category and tags filter to display data structure or algorithm-related problems.

It may sound perfect, but there’s one drawback to using Techie Delight. At the time of writing, it only supports three programming languages: Python, Java, and C++. So you’ll need to be familiar with one of these three languages to use the site. There’s also no editorial section and no discussions tab that you can use to seek assistance when stuck.

With over 600 problems on the platform, InterviewBit is another solid site for DSA practice. It categorizes its questions according to different factors including difficulty, topics, and companies. For DSA practice, use the topic filter to drill down the questions displayed by specific subdomains under data structures or algorithms. When you navigate to a question’s tab, InterviewBit goes a mile extra by including a Hints tab.

It divides the Hints tab into three, with increasingly detailed steps on how to go about solving the problem. Viewing a hint deducts 10% from your score. A suggested approach to the solution reduces the final score by half, and you don’t get a score at all if you view the complete solution. You can use this clever feature to learn, practice, and test yourself as you see fit.

Master Data Structures and Algorithms Using Coding Challenges

We’ve listed the best websites for practicing data structures and algorithm concepts. These sites allow you to practice DSA in various programming languages, including popular high-level ones like Python, Java, and JavaScript alongside even low-level ones like C, C++, and Rust.

Most of these sites include solutions and the thought process behind solving a problem, which can be helpful while starting your journey to DSA mastery.