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

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.

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.

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.

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.

"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!

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.

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.

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.

"Just like the real thing! Master job interviews, coding competitions, and your skills all at once." Perfect preparation for corporate coding tests! Improve your skills from basic to intermediate! This course contains only the essentials necessary for coding test preparation. Structured step-by-step from basic concepts to practical problems, you can improve your programming skills and practical sense at the same time.

Through this course, you can systematically learn core concepts such as basic tree concepts and data structures, search algorithms, tree application algorithms, advanced tree structures and applications, and practical problem-solving strategies.

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.

Learn Python from scratch by fully utilizing ChatGPT. Rather than tedious conceptual explanations, the focus is on students directly experiencing coding and developing problem-solving skills through example problems and practical exercises. After mastering Python's basic syntax, you can build your skills by solving various problems in Level 1 and Level 2. Furthermore, you can identify and supplement your weaknesses through an Exam structured like a real test. By regularly solving problems and utilizing ChatGPT, students can have a memorable learning experience without feeling bored.

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

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.

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!

Daily repetitive tasks like organizing emails, writing reports, and summarizing data... Do humans really need to do these manually? Does ChatGPT feel like it's just for chatting, and does automation seem too difficult? But even without coding, you can build practical automations in just 1 hour. This is a practical course designed to help non-developers automate workflows and reduce repetitive daily tasks using n8n and AI. By following along, you will create automation workflows that can be applied at work immediately. We've cut out the fluff and included only what you truly need. You will experience a transformation in the way you work, starting today.

✅ 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 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.

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.

A mediocre developer portfolio won't get you hired! Revealing the portfolio secrets that actually landed jobs at major IT giants like Kakao, Samsung Electronics, and Naver!

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 the easiest introductory course for those new to information security. You can get a feel for real-world tasks by experiencing the five core roles: planning, development, operations, assessment, and monitoring. Start building your own career roadmap for employment or a career transition.

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

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.

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

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.

The Code Puzzle Clear Challenge is a 4-week intensive training course based on "Learn to Code 1" in Swift Playgrounds, designed to develop "computational thinking" by giving commands to make a computer move as intended. By solving puzzle missions in each session, participants naturally learn to break down problems into smaller steps (decomposition), recognize patterns to organize repetitive rules using for-loops or functions, and make logical judgments to change actions based on specific situations. Beyond simply finding the right answer, participants reach a level where they can explain and refine "why they solved it this way."

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