I am sharing the most efficient study method I experienced while taking this course by Dalle (Daeyoung). First, try solving the problems and listen to the lectures. Most people will probably think, "Oh, this is just another algorithm problem-solving course." The important thing is that if you can't solve a problem while listening, don't torture your brain until it's solved; just watch the lecture. Since this is a practice stage anyway, there's no need to torture your brain to the point of losing interest. Just think, "So that's how Dalle solved it," and move on. (However, you must code along with him. This is important.) The real key point of the course starts from the second round. When you go through the lectures a second time, try solving the problems first without listening to the explanation. As you solve them, draw diagrams either in comments or on a pad. The core is to start with a brute-force approach and optimize it step-by-step. 1. During the optimization process, make sure to note down why you thought of that specific approach. Even if you feel like you can't forget the answer you've already seen, pretend to trick yourself and write down the causal relationship of your thoughts—even if it's just the imprinted flow of optimization. 2. If you can't solve it, write down in detail exactly where you got stuck moving to the next step. Then, while watching the lecture, write down Dalle's thought process that breaks through that stage and code along with him. It's okay even if you just memorize it. (Your brain cannot distinguish between perfect understanding and perfect memorization.) 3. Before starting the third round, thoroughly study the "wrong answer notes" you've written so far. Then, set a time limit—20 minutes for Easy, 40 minutes for Medium, and 60 minutes for Hard—and try solving them on LeetCode while explaining your thought process out loud or through comments. If the explanation doesn't flow smoothly or you get stuck, it means that's your weakness. In that case, watch the lecture for that problem again and repeatedly solve similar types of problems on LeetCode to turn them into patterns; this is great for supplementing your weaknesses. To Daeyoung, who is always sincere about helping junior developers! Thank you once again!