Course Database Validation Leetcode

[Cori Lenon]

Inthis article, we put three interview preparation platforms up against each other in the battle of LeetCode vs HackerRank vs StrataScratch. Let us compare these three interview preparation platforms which are used by people working in Data Science.

The first step of getting a role in Data Science is, of course, the interview. The job search process is a long and arduous road, and if you get past the initial screening process with your resume and cover letter, not to mention the first screening call, there is still the actual interview itself. Or multiple interviews, as is almost always the case. While there are common personal and behavioral questions you can expect to be asked, the technical questions relating to your understanding of Data Science can be harder to prepare for.

A variety of educational platforms have risen to serve this need, giving users vast libraries of problems to test their coding abilities and industry knowledge, with a range of pricing models, question types, and domain focuses. As we look to get a role in Data Science, which ones best suit our needs? Let's dive into the battle of LeetCode vs HackerRank vs StrataScratch and find out.

Established in 2015, LeetCode describes itself as a "new way to learn," hitting the milestone of over one million users back in 2017, and boasting of a library of over two thousand questions. The most popular interview preparation platform, Leetcode also supports 14 different languages, including (most relevantly to the Data Science industry) Python and MySQL.

A quick look at LeetCode shows why it is such a popular platform. Out of the 3 platforms we will dig into in this article, Leetcode has the most fleshed-out and user-friendly UI, with a clean interface and a variety of topics to choose from and dig into. The code editor is also extremely advanced, with customizations for themes, key bindings, and font size, in addition to an analysis of memory used and required runtime for the code you write. This is on top of other minor conveniences, such as the ability to adjust the amount of space the code block takes up while keeping the question in view, as well as the ability to add custom test cases to test during your submission.

LeetCode's questions are also known to have very straightforward text introductions that go directly into the problem statements you are trying to solve, with the added convenience of links to similar questions on the platform if you have any particular areas you want to drill down on. Most of the problems also include a step-by-step write-up that explains reasoning to the solution, sometimes discussing different potential strategies to solve the challenge. Company-specific interview questions also include specific tips for how you should think about each question, and approaches to incorporate into your thought process.

The number one feature about LeetCode that users talk about is the community. With over one million users, the discussion boards with each question work as a vital resource to gaining insight into how other people solve a problem, both in how they approach the question and in what mistakes they may make. The power of such a massive user base also means a diverse input of information, and most questions you click into will have hundreds upon hundreds of comments on the discussion board. Even if the official guided solution article is behind the paywall, you can still easily dig up helpful responses in the discussion thread, or even get some feedback on your thought process and code from the wider community.

Functionally, you can still get a fair amount of use from LeetCode even with only a free account. Even with premium solutions that are locked for free users, you can generally find good answers in the discussion boards.

However, a paid subscription does give you access to even more questions, sourced by popular companies, and even filters by the prevalence of those questions in interviews. The premium subscription also gives you little conveniences to the code block, including a debugger and autocomplete functionality, as well as miscellaneous resources such as help preparing for interviews through simulations.

Coming from a Data Science perspective, the biggest limitation about LeetCode is that the platform is focused on software developers and software engineers, and users outside of that field will not get as much value from the platform. This is reflected in the limited body of SQL questions on LeetCode, mostly under the Database and Data Steam categories. That limitation is also shown in the very direct style of LeetCode questions: while Data Science questions are complex and will often contain many assumptions that need to be spelled out, LeetCode's focus on algorithm questions makes it much easier to, despite their occasional complexity, write short, straightforward questions.

More broadly, LeetCode questions focus primarily on answering very narrow, specific problems that might not reflect on a real-world work environment. Even with LeetCode's Data Science relevant questions on databases and algorithms, the questions focus more on syntax than on thinking broadly about situations you might have to deal with as a data scientist. Knowledge of very specific case scenarios of how one particular edge case works is much less important than the broader problem-solving needs of Data Science. However, it can still be a good exercise to brush up on your coding abilities, and help you work on your knowledge of language-specific syntax, which is a necessary part of establishing a baseline for your coding abilities.

All in all, LeetCode is a solid, well-known platform with an active user base, and can be a crucial resource for preparing for your interviews. However, it might not necessarily be the best tool for those looking at Data Science.

Another popular interview preparation platform, HackerRank boasts of a library of over 91 million challenges and a user base of 11 million developers. Founded in 2009, the platform supports 43 different languages, though not all languages are accessible in every challenge. HackerRank is also the only absolutely free platform of the three that we are comparing in this battle of LeetCode vs HackerRank vs StrataScratch.

HackerRank is 100% free to use for developers, or users trying out coding questions to prepare for interviews. Instead, HackerRank is a popular platform for companies to use in their interview process, and uses those companies as its paying customers. The customer base includes over two thousand companies, including over 25% of the Fortune 100. This means that familiarizing yourself with the HackerRank platform is an important step in the interview process, as many data science companies do use HackerRank for their technical tests.

While HackerRank does use an in-platform currency hackos, their only current use is to unlock test cases. Even these don't realistically lock you out of anything on the platform, and are pure convenience in supporting your problem-solving process to explore additional test cases, outside of the ones already provided, to further explore the challenge. Hackos are not a monetized currency, and in fact are fairly easy to earn: solving problems, participating in contests, and even just logging in multiple consecutive days. The HackerRank FAQ states that they are planning to create more avenues to earn and spend hackos in the future.

Compared to LeetCode, HackerRank is much more geared towards data scientists and prospective data scientists, with a wider domain range across the industry to dig into, including machine learning, artificial intelligence, and algorithm libraries. There are also plenty of different tracks to explore to help you drill down on specific topics, such as regular expressions, data structures, and math, as well as language-specific tracks, covering Java, SQL, and Python. These tracks also have a progression of difficulty, with the earlier challenges being simpler introductory questions that get harder over time. This means HackerRank tracks can be especially useful to learn brand new topics from scratch, or just to brush up on any gaps you might have in your knowledge.

In addition to its library of challenges, HackerRank also holds a job board and certification challenges, as well as holding regular coding contests with a competitive ranked ladder. As many companies use HackerRank as a part of their interview process, in addition to familiarizing yourself with the platform, it can be a boon to your job search to develop your profile to show off your skills with the basic and intermediate certifications for different languages and domains. Even just being able to show off your HackerRank profile and competitive ranking on the contest ladders can be a valuable addition to your resume.

HackerRank's UI is slightly less developed than LeetCode's, though it still supports some degree of customization, such as support for EMACS and Vim, as well as tab space flexibility. The platform also has slightly more extensive solutions for each of its problems than LeetCode, with an Editorial tab for every problem that explains a handful of their test cases on top of the solution itself. Unlike LeetCode, HackerRank's code editor also includes autocomplete as a free feature, which is an additional convenience for non-premium users on the free platform.

Similar to LeetCode, HackerRank questions can be too similar to puzzles, a few steps removed from real-world problems you might face when doing "real work". Again, this can still help you scale up your coding abilities, setting the baseline for your skills. HackerRank's progression of difficulty in its challenges actually make this one of its main strengths, as going through a series of challenges can ensure you have a good degree of understanding of each concept or code language, in addition to helping to shore up any gaps in your knowledge. However, it is still important to recognize those limitations, where that may be a feature most useful to total beginners.

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