38 Companies Passed: Essential Algorithms for 2026 Coding Tests

I aim to help you understand the core concepts of Python within 60 minutes! I focused on the "Why" and "When" to use them, rather than just blind syntax.

In a world where every résumé looks similar, “differentiation” gets you hired. Over six weeks, learn four practical résumé strategies directly from a backend professional.

No coding skills? No problem! Turn your ideas into real profit in just 4 weeks. Use AI and the latest tools to build a website and an app simultaneously and launch your service right away.

"I have a backend technical interview in a week—where should I start?" The secret to answers that make interviewers nod in approval. Fully master the actual answer patterns of successful candidates from Naver, Kakao, Coupang, and Toss in just 3 days!

Beyond using AI just for copy-and-paste tasks, learn how to connect Claude Chat, Cowork, MCP, n8n, Supabase, and Vercel to actually automate repetitive work for non-developer office workers. Set in a fictional company called DingcoLabs, this course walks you through hands-on PM, marketing, sales, customer service, and HR scenarios to build a workflow automation system you can put to use at your company right away.

This is an introductory backend development course where you learn through understanding rather than memorization, and experience rather than theory. Instead of reciting a Googled definition when asked "What is JPA?" in an interview, this course will empower you to give an answer based on experience, starting with "Well, I've been through JdbcTemplate hell..." You will gain a deep, intuitive understanding of "why we use frameworks" by experiencing firsthand how 30 lines of pure Java ServerSocket code shrink down to just 7 lines in Spring Boot. After 6 sessions, you will walk away with a functional portfolio piece: a Todo List REST API built with Spring Boot + JPA.

AI is no longer a choice, but a matter of survival. Shorten development tasks that used to take 3 days down to 30 minutes; leave repetitive tasks to AI and focus on solving more important problems. Through AI-native development methods that are practical rather than theoretical, we will show you the definitive way to be recognized as an "AI-savvy developer" at your company.

You've probably written SQL using JdbcTemplate before, right? Everyone has likely had that experience of sighing while having to fix both the SQL and the RowMapper every time a single column changes. This course starts from that very pain. Doing a single SELECT with pure JDBC takes 35 lines. You open a Connection, create a PreparedStatement, iterate through the ResultSet, and if you miss a single close(), the server crashes. After typing through this hell yourself, when you finally encounter a single line of JPA's save(), you'll feel "this is why we use JPA" not just in your head, but in your hands.

We live in an era where AI can generate 10 files at once. However, if you can't track where the code changed, if it conflicts with your teammates' work, or if you don't know how to revert it—your productivity will suffer no matter how well you use AI. This course isn't just a list of commands like git add and git commit. It provides a visual understanding of the principles behind safely managing AI-generated code and merging it with your team's work. In just two hours, you will transform into a developer who can freely track, revert, and merge any code, whether it was created by AI or written by yourself.

If you ask an AI to "get the top 10 sales," it will whip up a plausible-looking query in no time. However, to determine if that query is actually correct, if the results of joining three tables are accurate, or if it's performing a full scan on 500,000 records without an index—you ultimately need a foundation in DB basics. This course doesn't cover anything overly difficult. In just 2 hours, you will learn the entire flow of SQL by coding along, covering exactly what you need to know before giving instructions to an AI. By the end of this lecture, you will no longer feel uneasy when faced with a query generated by AI.

LeetCode explained by Dalle, a Korean developer working at a Silicon Valley startup! This is a practical LeetCode problem-solving course that doesn't just provide answer codes, but compares multiple approaches for each problem, analyzes time and space complexity together, and explains why certain solutions are more efficient. First, we write the most intuitive approach and analyze its time/space complexity to identify bottlenecks and improvement points. Then, we explore alternative approaches applying various data structures and algorithmic techniques, comparing the performance differences and pros and cons of each method. Through this, it helps you develop problem-solving skills to design efficient solution strategies on your own when facing new problems.

Kakao Cote 6-week pass study method nerd scientifically selected algorithm/data structure extract

This is a career guide course that covers the entire process of landing a developer job or switching careers, including resumes, portfolios, technical interviews, and behavioral interviews. The theory section outlines the process of finding the right company for you, analyzing job postings, and preparing for interviews and coding tests.

This is an online lecture that systematically organizes pathfinding and spatial partitioning algorithms used in game production.

Here are some key competencies that are often overlooked by others in the fiercely competitive and complex semiconductor process job market.

Learn the principles of Diablo 1-style PCG dungeon generation by implementing its structure in the console, with the theme 'Technology Supporting Game Development in the AI Era'. Expand this to 3D in Unity to complete a generation pipeline equipped with seed-based dungeon generation, mesh placement rules, and debug tooling. Through sample code and hands-on practice, connect to AI-assisted art production workflows, enabling you to create immediately applicable dungeon crawler prototypes.

Are you using code written by AI without even knowing what it does? It’s not enough for it to simply work—you need to make it perform well, yet when asked, “Why did you implement it this way?” you find yourself at a loss for words. The source of that frustration is a lack of fundamental CS knowledge and an understanding of how GPUs work. Through this course, you will learn the principles applied to CPUs and GPUs, along with the relevant CS knowledge, enabling you to control AI and give it instructions effectively. You will also be able to avoid being replaced by AI at your current company or when seeking employment or changing jobs, and earn a higher salary.

When learning Swift, the iOS programming language, it can be confusing when multiple concepts appear all at once. That's why I created this course with the principle that "when understanding a new concept, only previously learned concepts should be used." So this course is meticulously designed with a sequential structure between concepts, where only one new concept appears at each stage, and no other unfamiliar concepts appear at all. One concept per minute, 180 concepts total. From the basics of variables and constants to understanding memory structure from a CS perspective, and even the latest syntax for asynchronous processing. In 3 hours, you'll learn 180 core concepts in the designed order.

You can understand the theoretical operating principles of the Kalman Filter through easy examples.

This is an introductory Python course based on interactive textbooks. Understand the principles of programming through a charming board game.

✅ Out of the entire series (1) ~ (7), (4) data structure, algorithm, object-oriented, programming language ✅ CS101 series lectures - From basic computer theory to the latest practical examples - Provides a wide range of basic knowledge

This course was created based on my personal experience passing the very first revised Information Processing Engineer practical exam, which had a pass rate of only 5.34%. The Information Processing Engineer practical exam can no longer be prepared for through simple memorization alone. In particular, the ability to read the execution flow of C, Java, Python, and SQL code to track results, as well as the ability to accurately distinguish short-answer concepts and write them as answers, has become crucial. This course is structured to help even beginners who are new to programming follow along step-by-step, covering everything from creating variable tables to tracking C, Java, Python, and SQL code, core practical terminology, and written exam subjects 1 through 5. Rather than being a video-centered course, this is a text-based course designed for fast reading and repeated review. It makes it easy to look up necessary parts again and focuses on practicing how to derive answers at the testing center by following the code and explanations directly. The 1st update covers the practical programming sections: C, Java, Python, and SQL. The 2nd update will organize core terms and concepts required for the short-answer practical questions and provide a "Stepper Simulator" to practice code tracking directly. The 3rd update will sequentially expand to cover written exam subjects 1 through 5. The Stepper Simulator is designed so that you don't just stop at reading explanations; you can understand how variable values change as the code executes line by line by following along yourself. If you have any questions while taking the course, please leave them in the Q&A. I will respond as quickly as possible to ensure your learning doesn't get stuck.

In this course, you can master prompt engineering techniques that can be applied immediately in practice using the OpenAI API. You will learn how to simultaneously improve efficiency and productivity in your daily life and work. In particular, we support you in gaining confidence for interviews by automating the creation of customized resumes and cover letters for your desired companies, as well as preparing for mock interviews.

Build your coding skills by implementing data structures in Java from the ground up.

Hear essential insights for developer career growth from the top 1% of developers.

Practical English Guide for Software Engineering | Great IT English

This is a partial lecture from the theory section of a comprehensive career guide course that covers everything you need to prepare for developer job hunting and career transitions, including resumes, portfolios, technical interviews, and personality interviews. The theory section covers the process of finding companies that fit you, analyzing job postings, preparing for interviews and coding tests, and everything you need to know to prepare your resume and portfolio.

When learning Swift, the iOS programming language, it can be confusing when multiple concepts appear all at once. That's why I created this course with the principle that "when understanding a new concept, only previously learned concepts should be used." So this course is meticulously designed with a sequential structure between concepts, where only one new concept appears at each stage, and no other unfamiliar concepts appear at all. One concept per minute, 180 concepts total. From the basics of variables and constants to understanding memory structure from a CS perspective, and even the latest syntax for asynchronous processing. In 3 hours, you'll learn 180 core concepts in the designed order.

Are you knocking on the door of employment, but finding it difficult? As a non-major humanities graduate and academy completer, I will share the "portfolio that actually works" which I used to break through and open the doors to employment after months of trial and error.

If you are worried about where to start and where to start studying because you need to take a SQL coding test to become a data analyst, then come to this seminar!