LeetCode is a coding and programming interview practice tool that helps beginners and professionals prepare for careers in technology. Some major companies rely on LeetCode or similar platforms to test applicants’ coding skills. However, students and professionals also use the platform to work with peers and expand their technical skills.
What Is LeetCode Used For?
LeetCode is a tech skills and interview preparation platform students, professional programmers, and employers use to learn, practice, and assess coding and programming skills. Part coding test, part community forum, and part interview preparation tool, LeetCode serves as a resource for current and prospective coders to expand their skills, learn from peers, and engage in coding competitions.
Professional software developers view LeetCode as “a tool that helps build and hone skills, offering direction on how to approach problems, which fast tracks user’s problem-solving capabilities,” says Geoffrey Bourne, software developer and co-founder of Ayrshare.
LeetCode has both free and paid subscriptions. While the paid or “premium” option offers a wider variety of problems or questions, students can still access a lot of content for free.
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Types of LeetCode Problems
Whether you’re using it to prepare for an upcoming interview or to develop fundamental coding skills, LeetCode offers problems to practice programming subjects like:
- Software engineering
- Computer science
- Data structures
- Algorithms
- System design
- SQL
- Dynamic programming
- Decision trees
- Machine learning and artificial intelligence
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LeetCode Questions for Interview Preparation
A core aspect of LeetCode’s platform is pre-designed question sets that focus on learning specific topics or preparing for different types of interviews.
LeetCode 75
The LeetCode 75 is a collection of 75 coding questions designed to give you a broad preparation for technical assessments. Most of the questions in this set are easy or medium difficulty, and LeetCode recommends spending one to three months working through the problems to prepare for a coding interview.
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Top Interview 150
Similar to the LeetCode 75, the Top Interview 150 question set offers a range of problems to prepare for coding or programming interviews. These questions range from easy to hard difficulty, so some problems may be more challenging for those just starting in programming.
SQL 50
The SQL 50 and Advance SQL 50 are sets of problems that test the full range of SQL capabilities to help you prepare for SQL-focused interviews and roles. The advanced set covers more challenging questions, while the base collection of 50 SQL questions generally ranges from easy to medium difficulty.
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30 Days
LeetCode has a few sets of questions for learning more fundamental skills in 30 days. For instance, students can complete the 30 Days of JavaScript challenge to learn and practice basic JavaScript skills through one question per day.
>>MORE: Discover what tech job is right for you.
High Frequency
Through its network of programmers, LeetCode collects some recently asked coding problems from tech company interviews. Currently, LeetCode has collections of frequently or recently asked coding questions in Amazon, Google, Apple, and TikTok internships. However, most of these questions are only available to premium (or paid) members of the platform.
Prepare for your interviews by learning commonly asked questions, both technical and non-technical:
LeetCode vs. HackerRank
HackerRank and LeetCode are platforms for building coding skills and preparing for interviews through interactive challenges.
The main difference between HackerRank vs. LeetCode is that LeetCode focuses more on interview preparation through broken-down challenges. On the other hand, employers often use HackerRank to test candidates’ skills.
Some employers do also use LeetCode for testing candidates, though.
Using either platform, professionals can test students and “really get an understanding on whether they’ll be an overall good fit, skills wise, on a project,” says Bourne. “So, essentially, they give us insight into a candidate’s abilities.”
Ultimately, when preparing for an upcoming technical interview, you can use either platform. However, if you know the company you’ve applied for uses one over the other, it’s better to practice on that platform. Using the company-preferred tool lets you get a feel for the user interface and better understand how the platform formats questions or problems.
>>MORE: Learn more about HackerRank.
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How to Prepare for LeetCode-Style Technical Interviews
If you’re preparing for a technical assessment, check the job posting carefully so you know what skills the employer wants to see. Once you know what to focus on, you can leverage platforms like LeetCode to make your interview preparation more effective. Don’t forget to prepare for other parts of the interview, too, like practicing behavioral interview questions.
>>MORE: Check out 15 interview tips to help you get the job.
Go In Prepared
LeetCode can help you prepare for the types of questions an interviewer might ask, but it’s not ideal for those without prior knowledge. You have to know how to code at least a little to begin diving into LeetCode problems and preparing for technical interviews.
One way to learn coding is through college or university courses. Another is through coding bootcamps:
Develop Understanding Instead of Memorization
Memorizing the answer to a problem may help you pass that challenge on LeetCode or answer a specific question in an interview, but it won’t make you a great programmer. Additionally, that method will leave you lost if the interviewer asks follow-up questions.
Rather than just memorizing an answer, seek to understand how it works on a deeper level. LeetCode’s forums can be a great place to talk with professional programmers if you’re stuck or struggling to wrap your head around a particular concept.
Start Early
Preparing for technical interviews takes time. The earlier you start, the more prepared you can become. Additionally, starting early allows you to find the topics or concepts you struggle with and really dive deep into them. Some LeetCode practice courses recommend taking over three months to work through them, too.
Practice Often
“The more you practice, you’ll find answers are almost intuitive,” says Bourne. “Building up your knowledge through peers is invaluable.”
Practice truly makes perfect when it comes to building programming skills. Through consistent practice, you can develop a deeper understanding of core concepts. Additionally, with LeetCode and other online forums, you can practice with peers, allowing you to see different approaches to problems.
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