Skill Improvement Algorithm Coding Test 40-Day Completion (by HaruCoding)

Baekjoon Bronze 4·5 Difficulty Algorithm Beginner Roadmap Starting with 3-4 Problems Daily

Baekjoon Bronze 3 Level Core Problem-Based Coding Test Fundamentals Training

This course is designed to help entry-level professionals preparing for employment at game companies get ready for coding tests.

This is a Java course for beginners. It is designed to be easy to understand for those who are new to Java.

This course is a process of learning the basic theories of data structures by directly implementing them using JAVA programming. It is designed to go beyond simply learning theory, allowing you to gain a deeper understanding of the principles of data structures by implementing them with actual code. Learners will theoretically study core data structure concepts such as arrays, stacks, queues, lists, trees, and graphs, while simultaneously experiencing the actual operation process by implementing them in JAVA code. Through this, you can develop logical thinking and problem-solving skills rather than simple rote learning, and enjoy the synergistic effect of mastering both programming and data structures together. 👉 Upon completing this course, learners will master the basic concepts and structural characteristics of data structures, as well as the ability to implement and apply them in real-world development environments, building a foundation for designing more efficient and robust programs.

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.

It explains the basic concepts step-by-step and helps you build practical knowledge by creating various applications that run in real-world web environments. By completing this course, you will be ready to be deployed immediately as a professional programmer.

In this course, you will learn Kotlin syntax, how to safely convert Java projects to Kotlin, and how to code in a Kotlin-like manner. Learn Kotlin based on practical code and use it yourself to enjoy its advantages.

Refactoring is one of the basic skills that a software engineer should have. This course is designed to explain and practice various code smells and refactoring techniques in a more practical way using IntelliJ and Java.

Scala allows you to write much more concise and robust code quickly, while still leveraging the experience you have gained as a Java developer. This course is designed for Java developers to quickly understand the overall look of Scala based on their existing Java knowledge. If you are an existing Java developer, you can learn Scala very easily.

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.

When fixing legacy Java code, determine what to change and which behaviors to preserve. In the existing IntelliJ IDEA hands-on exercises, you directly review code changes, while in the 16 newly added theory lessons, you learn about names, functions, duplication, responsibilities, calling contracts, and validation criteria.

We present various clean coding techniques.

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."

This course is a video lecture that systematically covers the core modern JavaScript syntax essential for learning React.js and Vue.js frontend development. It is structured to help you develop efficient coding skills through ES6+ syntax, latest features, and practical examples that can be directly applied to work and learning.

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.

In [Java Practical Project: UI Edition], we will create a movie information application that operates solely on pure Java technology using JavaFX. This course is designed to help you deeply understand the "structure connecting screens and logic" by directly implementing UI event handling, asynchronous logic, and user interaction flows in Java before moving on to web and smartphone apps. You will train your structural thinking by separating business logic and UI through integration with Spring Core, and learn how to solve UI performance degradation issues that may occur when fetching movie information from external APIs using asynchronous processing. Through this, you will clearly understand the principles of data flow, event listeners, and thread-based asynchronous processing, elevating your understanding of the Java language itself to the next level. In short, this course is a "practical stage to experience the essence of UI and the core of asynchronous processing with Java before moving to the web." Do not forget that this is not a class for just typing along with code, but a learning experience where you can personally master the principles of connecting UI and logic.

Knowing design patterns will make it easier to learn not only Spring but also many other technologies and programming languages. It will also help you develop more flexible and reusable object-oriented software.

JAVA is a programming language, just like the C language. JAVA can be used for web development and application development, and here we will learn JAVA before doing web development.

IntelliJ IDEA Conf 2025 is an annual online conference hosted by JetBrains that provides valuable sessions for Java and Kotlin developers. It covers various topics including AI adoption, Spring Boot, Gradle, Kafka, database management, and also shares insights on cloud integration, secure coding, developer performance improvement, and advanced development techniques. This conference is open to both professional and beginner developers, offering opportunities to explore the latest technologies along with productivity tips for writing high-quality code faster.