As we all know, National OI is (mostly) one of the stepping stones needed for one to be able to participate in IOI. But, in some countries, this National OI usually consists of recurring characters involved inside the problems we have to solve. One of the famous ones are USACO with their recurring characters being Bessie the cow and Farmer John. While in my country (Indonesia), Pak Dengklek and his ducks (Kwak is usually the most famous one) are the recurring characters in the National OI.
Now, out of curiosity, what are YOUR National OI's mascots or recurring characters? It's fine if your country doesn't have one :>.
(picture unrelated)
We don't really have characters in Serbia. However, there are some problem themes that are quite common. The most famous one probably being the theme of committee denying complaints.
Clock in Moldova.
In Vietnam, the national OI is called the "Vietnam Olympiad in Informatics" which abbreviated as "VOI". The word "VOI" means "elephant" in Vietnamese and this coincidence led to the elephant becoming the mascot of our national OI :P
elephants eat banh mi
Still it is just a fun informal way of naming the contest in the Vietnamese community but not a recurring topic in the statements. The statements so far seemed to only have random people with random names and random problems, without any major theme throughout the years.
Definitely would be nice if one day the statements start to use the animal as the official theme itself for the contest.
Mr. Malnar (Croatia)
Not really a mascot, but it is quite common to use Berland (Berlandia, rus: Берляндия) as a country in problems statements in Russia. Some examples are: 723D - Lakes in Berland, 732F - Tourist Reform, 1322E - Median Mountain Range
Mike Mirzayanov explained the origin of the name in this comment (in Russian).
It seems to me that Berland's first memories date back to around 2000. In Saratov at that time, we often used the slang verb “berlyat” to mean “eat food” (for example, “who is going to berlyat?”). In one of the tasks I needed a fictional country, an example of absurdity and bureaucracy. Berland turned out to be a good choice. From then on it went.
It's funny that such a geographical name is actually used: in Canada and in Norway.
Petya and Petya++ in Belarus
Sometimes I like being Egyptian (we haven't static characters).
Same in Syria. It just depends on who's writing the problem.
Yeah. Same too!
Petya
We have a whole host of them in the UK. Alpha and Beta complexes (full of spies), "The Masked Lady and the ..." film series, the group of villages known as "The Endians", the company of Widget, Whatsit & Doodah (est. 1862); there's also the occasional problem involving the Greenlight Casting Couch film studio. And it's amazing how many different problems can be formulated within the cutthroat world of pigeon racing.
Sarah Bitan and Granny Smith in Israel, basically everything that's related to apples
Farmer JOHN and his cows
In Vietnam, the unofficial mascot is an elephant, because "VOI" means "an elephant" in Vietnamese. However, if my memory serves me right, an elephant has never appeared in a VOI problem before.
An and Binh = Alice and Bob have appeared several times in VOI, but not in every year, so I don't think they are the recurring characters of VOI. However, in recent years, the problemsetters have tried to integrate a story into the problemset.
For example, in VOI 2022, the story was about a student named Nam, who was the class monitor back in high school (problem 1), an amateur graph theory reseacher (problem 2), and a Wi-fi system designer (problem 3). He then became a competitive programmer (problem 4), wrote his own computer graphics program (problem 5), and the program had a complex image transformation (problem 6). By solving these problems, you'll basically experience the life of Nam in 2 days.