The lectures are about 15~20 minutes per episode. The problem is that each lecture consists of a problem + solution. Since I solved the practice problems without looking at the answer sheet, it took me at least 3~4 hours and at most several days for one lecture (Binary trees are really hard ㅠㅜ ㅋㅋ) If you have finished any C language lecture, I recommend that you listen to the appendix of Mr. Ttaebae. You will review all the functions you learn in the C language and learn how to use them while creating your own programs and implementing data structures. My biggest worry was that I didn't know the right direction for my development studies, especially since I am not a major, but I am following the direction set by Professor Hong Jeong-mo, who is a former computer science professor and has achieved success as a senior engineer at Facebook.