Step-by-step explanations that even beginners can easily understand make coding tests that once seemed daunting clear and approachable. Learn only what you need and apply it to real problems right away!
2,896 learners
Level Basic
Course period Unlimited
Reviews from Early Learners
5.0
이한희
While I was busy with a project, I didn't have time to prepare for a coding test, so I was looking for a place to prepare quickly in a short period of time when I applied for a job, and I found out about DingCodingKo's lecture that I usually enjoy, and I purchased it and am taking the course. It is most important to do algorithms consistently, but I think it is a good lecture for those who need a systematic curriculum to study in a short period of time like me. The official curriculum period is a 5-week lecture, but the explanation is good, so you can quickly learn the theoretical content, and assuming you invest a little more time, I think it will be enough to study in 2 weeks if you have coded before. The theoretical study and simple practice are good, and it is also good to solve the problems that came out in the actual coding test in the last week's lecture. If I listen to all of this lecture and solve coding test problems on my own, I think my worries about coding tests in employment will be reduced!
5.0
자유곰
Hello. I am a developer preparing for a job change. I have been learning algorithms from Baekjoon and Programmers for a long time, but I couldn't motivate myself to do it alone, so I looked for a lecture. Since I am currently using JAVA, I initially thought that Python was a language that I would learn later. However, after taking a sample lecture on other algorithms and being dissatisfied, I watched Dinkocodingko's sample lecture. The reason I decided to pay right away is that the tone of his voice suited me so well. I should say that it went straight into my ears? I was worried because I usually pay a lot of attention to the teacher's learning method, but it suited me so well! Since the tone of his voice is so good, I don't get sleepy, I can concentrate well, and it goes straight into my ears 😊😊 However, it's not just the tone of his voice that's good, but the way he teaches is not just about solving problems, but he really teaches about algorithms in detail, so I'm satisfied. I will definitely finish the course and try to change jobs 😊😊
5.0
가람
It's been quite a while since I systematically studied algorithms. In practice, I often use libraries or frameworks, so I have fewer and fewer opportunities to directly contemplate and implement algorithms. This lecture allowed me to reorganize from the basics. In particular, I was impressed that it not only explained the concepts but also covered the way of thinking and approaches to solving problems in detail. Thanks to this, I was able to not only recall the concepts I had forgotten, but also regain the habit of thinking about how to write more efficient code. I think algorithms are not just for coding tests, but also greatly help to improve problem-solving skills. After building my basics through this lecture, I feel more confident in approaching new problems in the future. I highly recommend it to those who want to review from the basics!
Algorithm
coding test
coding test
I passed the coding tests for all of the companies below.
Naver, Kakao, LINE, Coupang, Baemin, Karrot, Zigbang, Yanolja, KakaoBank, MyRealTrip, Hyperconnect,
Kakao Mobility, Naver Webtoon, Works Mobile, Banksalad, Ohouse ...
Isn’t that old news? I changed jobs by taking coding tests as recently as last year. I’ve experienced the coding tests currently given by companies. So I know what to prepare and how far to go.
Studying for coding tests without a clear purpose? You no longer need to. I’ll teach you exactly what you need to know to get hired. Learn compactly and pass every coding test.
2025/02/16 Travel Wallet accepted **Mr./Ms. H.
2025/07/31 Final acceptance at 3 companies, Mr./Ms. Oxx
Learn algorithms easily with real-life examples
Capsule Hotels and Cargo Holds
Laundry Baskets and Amusement Parks
Shortest routes to the emergency room and to work
Memorable analogies and explanations you won’t forget once you hear them
Algorithms Made Clear Through Visualization
Sorting Processes Through Animation
Understanding Tree Structures Through Diagrams
How Stacks/Queues Work, Step by Step
Understanding the DFS/BFS Traversal Process Through Illustrations
Coding Test Preparation
Solutions to actual Kakao, LINE, and Samsung exam problems
Analysis of the Latest Question Trends by Company
How to Find Hints in Problems
How to determine the solution approach based on the range of the input values.
Continuous growth support
An active online community is provided
Real-time Q&A and feedback
Sharing and discussing various solutions
Vivid reviews from successful applicants at each company
📌For complete beginners
It was created for beginners who have never learned algorithms before.
We start by explaining why this code is used and how to arrive at that idea, then go into detail about how the values change when the code is actually executed.
Still, you may not fully understand it, so at the end of the video, I’ve also included a visualization of how the algorithm works.
📌Just diving straight into problem solving?Absolutely not.
Rather than simply solving problems, I’ll methodically teach you the thought process for how to approach and solve them when you encounter a problem.
Algorithm problems aren’t designed to be solved only by math geniuses. Brilliant insights? Eureka moments? Absolutely not.
Each individual element that makes up a problem contains clues about how to solve it. I’ll show you how to pick up those clues.
📌 Community Management
Nevertheless, you may still have questions or encounter something you don't understand.
It can naturally happen with online courses.
So, we’ve created a community where you can ask and answer questions in real time.
Feel free to join us and ask any questions you have. Also, share algorithm solutions with various developers and try solving them together.
📌 60% theory, 40% practice
Starting with detailed theoretical explanations and ultimately working through actual problems given by companies, this curriculum covers it all.
I don't know where to start with algorithms.
✔ If you’re new to algorithms and want to learn the fundamentals systematically from the ground up
I don't understand how to solve the problems.
✔ Those who want to properly understand the process and principles behind solving problems
Studying alone is too difficult
✔ Those who want a learning environment where they can grow together with others
Actual successful student Seongxx (starting salary of 43 million won at a startup)
Actual successful student ㅇxx (starting salary at a mid-sized company: 4,800)
Depending on the stack you’re applying for, I heard the language used for coding tests is predetermined—for example, JavaScript for frontend and Java for backend?
That's right. There are cases where a specific language is required.
I took coding tests at 38 places and encountered this at only two of them.
At almost all the places you apply to, there are generally no restrictions on the programming language.
No matter how you express it, interviewers also know that ultimately, the ability to think through and solve problems is what matters.
You may be worried because it isn’t a language you’ve already learned.
However, I think it is necessary to understand it as easily as possible with Python.
Algorithms are difficult enough already, and when complex syntax is mixed with complicated logic, the code becomes much harder to understand.
When you first study it, it’s best to understand it as easily as possible, and then try expressing it in a more difficult way later.
It’s also a good idea to first understand it through Python and then learn how to express it in your own language.
If you understand the logic using Python, you can definitely express it in Java.
😨Ultimately, a programming language is just a means of expression, and understanding the problem is the most important thing.
And the easiest language to understand and solve problems with is Python.
[Updated July 20, 2025]
We have added supplementary code so that you can also solve the problems in Java and JavaScript, as many students requested!
We have not added explanations in those languages, but we hope you will use this as a good opportunity to review by looking at the same logic implemented in another language!
There is a special benefit available exclusively to those who take the course.
It contains carefully selected special algorithm problems based on the actual problems encountered while taking 38 real-world coding tests.
Please consider this a spe.cial. problem set created for those who want to study additional problems beyond the theory.
This problem set will be continuously updated, so you’ll be able to prepare for algorithm interviews in line with current trends!!
(This workbook will be provided as a link in the form of a Notion page!)
Claim yours after verifying your course review in the algorithm community!
(I’ve explained how to verify it in the very last lecture __)
That's not all.
We’ll also provide a developer job preparation guide (resume, portfolio, and more)!
Through KakaoTalk Plus Friend
🎟 We will send you a discount coupon 🎟
(15% off, cannot be combined with other discounts)
Pycharm IDE 3-month free access pass!
In support of your development studies, we have prepared a special benefit through our collaboration with JetBrains.
With the promotion code below, you can use PyCharm for free for three months!
✅ Promotion code: HYUNJOONPARKxJB
✅ Benefit: A 3-month free pass for one JetBrains IDE (e.g., IntelliJ, PyCharm, WebStorm, etc.)
✅ Valid through: December 31, 2026
✅ How to use: 😀
1. Go to the official JetBrains coupon registration page
2. Enter the code, then select your desired IDE
3. Check the license issued via email
⚠ Important notice:
This code is only available to new users who are using JetBrains for the first time.
(Only those who have never used a paid JetBrains license before can register)
(You can create new Google email accounts and do it indefinitely)
You may think, "Why does that matter?", but many courses are uploaded as-is without being reviewed.
This course underwent two rounds of review to carefully check the subtitles and context, enhancing its overall quality.
It was designed so that you can fully understand the content using only the textbook. We have organized and presented the textbook’s content systematically so that you can save your time and learn as efficiently as possible.
Among the course feedback, there was a comment saying, "It would be nice to have more example problems."
To reflect this, we added bonus problems throughout the lecture materials.
I think you can consider the problems with the 🎆 icon to be bonus problems without separate solution videos.
Added a link to download the textbook PDF
3-5. Added an explanation of how to further improve the stack — thanks to zz gg.
1-5. Added an explanation of the criterion for the first non-repeating character in Finding the Mode - thanks to Oh Subin.
3-9. Added an explanation of the condition that, among songs with the same number of plays, songs with lower unique numbers are included first - thanks to sonjs7554.
4-2 Fixed an animation error in the video - thanks to 애롱님
3-3 Corrected the selection sort output value error in the textbook - thanks to Yudev
Added Java and JavaScript problem-solving code
Practical Data Structure Library Comparison Table - thanks to BruBru
Updated boundary value logic and added boundary value tests for Week 4 Homework 1 - thanks to 한달안에 끝낸다.
Added code and an explanation for BigInteger in the 4-8 DP section - thanks to xuv2‑nim
5-4 Input/output case correction - thanks to June‑nim
3-5 Input/output case fix - thanks to giving0414.
3-5 ➕ Isn’t there a way to improve it further? Input/output case revision - thanks to junnkyuu.
5-9 Added an explanation and course material on how to handle failing Programmers test cases - thanks to giving0414.
1-10 Description revised - thanks to Kim Ji-hyeop.
Added Q&A about two-pointer techniques in 2-10 - thanks to Myeongseok.
Sharing the behind-the-scenes story of making it to the final interviews at Coupang and Yanolja — a sixth-year developer’s job-switching story across 24 companies [ep 5]
2021 ~ 2022: S Coding Club Algorithm (data-structure) Tutor
2022 ~ : Runs the coding YouTube channel DingCodingCo (featuring a variety of content related to developer employment)
2022 ~ 2023: Server Developer at Viva Republica
Never give up on a student 🦈
Operates a developer job-hunting community
✅ Join the KakaoTalk chat: https://open.kakao.com/o/gPI6kTUg
✅ Join Discord: https://discord.gg/X74q5Yw3Sv
If you have any doubts!! before enrolling.
Should I be taking this course right now?? If you’re wondering, please feel free to contact us anytime via the KakaoTalk channel!!
😍 I’ll do my best to answer your questions 😍
The course uses PyCharm. The Educational (free) version works just fine!
I’ll share everything via Notion!
Basic Python knowledge (If you have never learned it before, you can watch my free Python course first!)
If you can understand the Python proficiency test video, you have enough background to take this course.
Who is this course right for?
Those who are just starting to prepare for coding tests
Those who feel overwhelmed by the vast amount of algorithm study material
Those who need problem-solving methods that can be applied directly in real-world situations
Beginners who need explanation-focused teaching and step-by-step approach
Those who want to learn only the core algorithms that reflect the latest exam trends
Need to know before starting?
A very slight introduction to Python
Inflearn Verified
Career Verified
20,788
Learners
2,061
Reviews
369
Answers
4.9
Rating
30
Courses
Park Hyun-jun · Dingcoding Co
POSTECH graduate · Backend development experience at Toss · Inflearn instructor
20,000+ cumulative Inflearn students · 2,000+ course reviews · 4.9 rating
Based on the Inflearn instructor profile, verified on 2026.10.03
Just nine months after starting to create courses, I was featured as one of Inflearn’s top-earning instructors. An Inflearn interview also features the story of a 60-year-old non-developer who completed a website.
We explain everything clearly, from why it is needed to how it is used on actual screens. Starting where beginners typically get stuck, we show you the process of building, clicking through, and fixing things yourself. In this challenge as well, leave the code and illustrations to Codex, and focus on judging the game's rules and results.
Inflearn interview: https://www.inflearn.com/pages/interviewdingco
All
56 lectures ∙ (15hr 33min)
17. 2-3. Class
10:06
All
454 reviews
5.0
454 reviews
Reviews 24
∙
Average Rating 5.0
5
I bought this course because of the thumbnail, but the content was even better. I majored in it and have experience as a developer, but algorithm problems were always difficult. I am gradually gaining confidence while taking this course😊 I set a goal of completing the course in 5 weeks, so I hope I can finish it well!! - Structure: Each topic is well organized step by step, so it naturally connects from basic data structures to actual past exam questions. In particular, I liked the fact that various approaches were introduced in the process of solving each problem. - Teaching ability: The explanations of the Dingcoding instructor are amazing, so it is easy to understand even complex algorithms. Even using visualization data👍🏻👍🏻 - Practical application: It doesn't stop at simply explaining the theory, but also covers solving actual problems and analyzing efficiency, so I think it will be very helpful for actual coding tests! Recommended for: I highly recommend this course to those who are preparing for coding tests or want to systematically build up their algorithm skills. If you have some understanding of Python grammar, I think you will gain a lot from this course. Rating: ⭐⭐⭐⭐⭐ (5/5)
ㅋㅋnim!! Thank you so much for the detailed course review!! 😭😭😭😭 I really hope it was helpful!! Keep up the good work!!
Reviews 1
∙
Average Rating 5.0
Edited
5
I kept putting it off every day, but I've pulled myself together and started again. If you're encountering this for the first time, I think this will be the best course. When it comes to solidifying the basics, I doubt there's a better course at this price. What I hope for: It would be great if there were courses on more advanced algorithms after the basics.
It was impressive to hear that you started again after putting it off. I am truly glad that it helped you build a solid foundation, and I will keep your request for advanced algorithms in mind.
Reviews 2
∙
Average Rating 5.0
5
I'm not a developer and I want to change jobs, but I had absolutely no knowledge of coding tests, so I purchased this upon a friend's recommendation. It's still early, but the explanations use examples and analogies, and they're presented in an easy-to-understand way, so I seem to be grasping it quickly. I will definitely complete the course and nail my job change! Wish me luck!!
It makes me feel truly proud to hear that the metaphorical explanations helped you understand, especially since you started with no prior coding knowledge. I'm rooting for you to achieve your career change goals by the time you complete the course!
Reviews 29
∙
Average Rating 4.7
5
The instructor explained everything in detail, making it easy to understand even for those who are new to the subject. The visual aids at the end were also easy to follow, so it was very helpful. - What I would like to see: It would be great if there were explanations and problem-solving for complex algorithms that might come up on the CoTe, such as the Bellman-Ford, BFS, and Floyd-Warshall algorithms.
Reviews 1
∙
Average Rating 5.0
5
It's been quite a while since I systematically studied algorithms. In practice, I often use libraries or frameworks, so I have fewer and fewer opportunities to directly contemplate and implement algorithms. This lecture allowed me to reorganize from the basics. In particular, I was impressed that it not only explained the concepts but also covered the way of thinking and approaches to solving problems in detail. Thanks to this, I was able to not only recall the concepts I had forgotten, but also regain the habit of thinking about how to write more efficient code. I think algorithms are not just for coding tests, but also greatly help to improve problem-solving skills. After building my basics through this lecture, I feel more confident in approaching new problems in the future. I highly recommend it to those who want to review from the basics!
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