The secret to passing 38 companies: Essential algorithms for the 2026 coding test

"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!

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.

Beyond simply copy-pasting with AI, you will learn how to actually automate repetitive tasks for non-developer professionals by connecting Claude Chat, Cowork, MCP, n8n, Supabase, and Vercel. Set against the backdrop of a virtual company called DingcoLabs, you will follow hands-on scenarios for PM, Marketing, Sales, CS, and HR to build work automation systems that can be applied to your company immediately.

In a world where every resume looks the same, "differentiation" is what gets you hired. Over the course of 6 weeks, learn 4 practical resume strategies delivered directly by an active backend professional.

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.

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.

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.

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.

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 course is for job seekers and career-changing backend developers preparing for coding tests with JAVA. We clearly identify question types by analyzing 195 actual past exam questions.

Let's perfectly prepare for the second coding test (implementation test) by solving 10 problems created with reference to front-end coding tests given by actual companies!

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.

I hope that through this course you will gain a clearer understanding of grammar and gain confidence in solving problems.

I have summarized the steps required to get a job as a front-end developer into 7 codes. I didn't have a senior developer, so I was vague when I was looking for a job, but don't worry anymore. 😀

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

After using it for 14 days starting immediately upon release, here are the reasons why I recommend Claude Code (AI Coding) to everyone—from job seekers to industry professionals—as something they can apply right away.

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 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.

Practical English Guide for Software Engineering | Great IT English

Developer interview taught directly by a senior software engineer who went through Naver and Amazon and is currently at Microsoft!! This lecture focuses on the "developer interview" rather than the "coding interview". When hiring a developer or, conversely, when changing jobs or seeking employment, the "coding interview" is never the only thing that determines success or failure. Through this lecture, I hope you will learn more about how to hire a developer or prepare for a change or seeking employment.

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.

This is a game development & algorithm course that focuses on the algorithms and principles of 2D game development from the ground up using Windows API and C++.

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.

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!

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

This course is for those preparing for the CosPro Level 1 exam, covering the COS Pro Level 1 sample problems released by the exam organizer, YBM Net Co., Ltd.

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.