Professor of Seoul National University who uses two last names properly.

(1)a free bulletin board
(2)This is hilarious lol
(3)You’re good at this.
(4)As the country was caught up in a trend, the law was revised to use all of its parents’ last names. After this generation, the length of the last name increases at a rate of 2. For example, if Choi Jeon Doo-hwan and Park Yi-soon marry Jae-yong and Park Jeon Ji-sook give birth to Sora, it became too difficult to manage the last name. Accordingly, the state decided to remove all overlapping parts of the people’s surnames and to make the remaining surnames alphabetically. For example, if Kim Bak-bak removes duplicates from the last name of a person named Choi Jeon-cheon, Kim Bak-bak becomes Choi Jeon-cheon-bang. If you sort this in alphabetical order, Kimmabakbang becomes Jeoncheon-cho, and this becomes the person’s new surname. Assume that there is no two-way surname like Namgung.To do this work for all citizens, we need an efficient algorithm. In order to make this work efficient for sufficiently large ns, we decided to remove overlapping castles using a red black tree and then extract them alphabetically.
(5)This is just a sketch, and you’re more specific about the process of achieving this goal, so that you understand this process, and give a representation of the average performance time of this method, which is an asymptotic expression of gender length 2 and the number of different sexes. This cannot be ignored in the analysis process because k may be a very small value or a large number close to n.
(6)What kind of fad is the country?