CEOI 2025 Blog

Impressions from the Central European Olympiad in Informatics in Cluj-Napoca, Romania, from 7-14 July 2025.

Johannes Kapfhammer
News

Hey, have some fun with this editor. The delegation consisting of Yuhua Su, Jonathan Braun, Myriam Faltin and Zeno Orglmeister with team leaders Johannes Kapfhammer and Cheng Zhong were representing Switzerland at the CEOI 2025 in Cluj-Napoca, Romania. Below we write about our experiences at this event.

Monday, July 7 (Zeno)

The commencement of our journey took place at Basle-Mulhouse airport (LFSB). Our plane was to depart at 15:50 local time, so naturally we had to arrive extremely early, at 13:00. Rumor has it that Cheng was unsure about the optimal time to arrive at the airport and therefore asked ChatGPT™ for high-quality airport advice.

The technology of the security check at Basle-Mulkhouse airport is slightly less capable than its counterpart at Zurich airport, and of course no match against the cutting-edge technology used at Geneva Contrin International Airport [1].

As we had some time before our departure we went to eat lunch where Cheng got scammed and paid CHF 2.50 for 500ml of water. During lunch we noticed that our plane was delayed by a whopping 5 minutes, which would’ve been a cause for celebration at Zurich airport. There was also a lot of talk about terrorists.

After finishing lunch we made our way to the gate, but not before engaging in some gambling where we studied stochastics and won airport merch, EuroVision merch aswell as USB-A, USB-C, microUSB and Thunderbolt cables (except Myriam, who got nothing useful). Once there we were pleased to discover that our plane was expected to be on time once more. The reality however, was very different. Our plane arrived about 30 minutes behind schedule.

When we were finally able to board Jonathan and Myriam were fighting over the window seat. Little did Myriam realise that this was Jonathan’s first time on a plane. After boarding was complete, we waited another 15 minutes before pushing back, and then the real fun began. Due to the delay we missed our departure slot and were assigned a CTOT (Calculated Take-off Time) one and a half hours in the future (from that point), but most didn’t understand why. This resulted in a delay of over two hours, something that wouldn’t have happened at Geneva Contrin International Airport. In total we spent over 5 hours at the airport, thanks to ChatGPT’s accurate calculations.

As it was Jonathan’s first time flying we explained to him what would happen if the DHL plane next to us would crash into our plane, how “fast” planes are when taxiing, how lift works, what turbulence is, how the cabin is pressurized, what to do with babies during an emergency landing and how the plane could land automatically. Myriam even brought a book describing how to land a plane if you fell out through the cockpit window.

So at about 16:15 local time we were finally able to take off and depart Basle-Mulhouse airport from runway 15 on the ELBEG7S departure. The flight went smoothly and we even discovered what clouds are and we held high-level discussions about aviation.

Our flight experience can be summarised in one simple video: [2]

When landing at Cluj-Napoca there was some confusion on the leaders’ end about timezones, but we were able to conclude that due to physical limitations the aircraft did in fact not fly twice as fast as intended. The final delay was roughly two hours.

[1]If you go through the correct lane
[2]Toilet: … Nice!

Thursday, July 10 (Myriam)

We first ate breakfast (not all completely at the same time, as every day, and still at a different table than Johannes and Cheng, but with Hanka). Thursday was the excursion day, is there a better occasion to test the new bottle speaker that we got? I don’t think so. But because the water in Cluj tasted bad, I only took the speaker part.[#]_ We took the bus to Salina Turda (a salt mine) and they were different shifts, so once in Turda, we had to wait the last group. So they were dozens of participants, leaders and guide standing half on the road to go to the parking. We were basically just standing on a non-pedestrian sign, what a great idea! We got some paper bracelet, the kind that you can’t remove without breaking it. But it is in fact a bit useless if you can put it yourself, so maybe in a way it’s actually large enough for you to remove it. In that case, you can also just decide to not just have a boring paper bracelet, but an interesting Möbius paper band! When the last group arrived, we started the guided tour of the mine. We went next to a huge cave that had really big echo. What should we try to shout? SOI? Stofl? Binna? [3] Then we went to the central part of the mine which was ~40 meters under the ground, so we had to take quite a lot of stairs because we didn’t know there was a lift. How do you imagine a salt mine look like? I guess just some small corridors that lead to an empty cave, with maybe a toilet somewhere, that would have been nice. Well, in this case you are COMPLETELY WRONG! They were in fact a souvenir shop, a mini-golf, some billiard table, a Ferris wheel [4], and even a lake with boats on it!

The CEOI team inside the salt mine.

After that, we had to get out of the mine because they were waiting for us for the lunch. So, as we learned from our precedent mistake, we went to the queue to take the lift, but it was even slower that the hotel lift, so it would actually have probably taken more than 30 minutes to finally be able to take the lift, so we had to take the stairs, but this time to go up. Then we went to lunch in a fancy restaurant with in front a fountain with a huge statue of a horse’s head. Unfortunately, all the tables were full, but there was a mezzanine, but we were not supposed to eat there for some reasons, but they finally set a table because they didn’t have any other option. At some point during the lunch, someone told us that the show[#]_ was going to start within ten minutes, and a few seconds later someone told us that we absolutely had to go because it was immediately starting. Spoiler alert: the ten minutes were way more right. The show was a horse training one. After it we went to some hills [5]. We basically went up the hill, looked at the view, played the toilet video [6] with the bottle speaker (without the bottle), looked at the view again, played the video again, looked at the view again, played the video again, and went down the hill. Then we went back to the hotel, ate dinner, played games and went to sleep at a reasonable time.

[3]that was actually a mistake because the sound is way better with the bottle part, especially if it’s full of water, but I still don’t know if it was intentional.
[4]we finally decided to just shout “Toilet, nice.” For the reference, you should read the first day of the blogpost, but everything started in Slovak Camp, but unfortunately the blogposts doesn’t seem to mention it :(
[5]that unfortunately didn’t seem to work
[6]which show?
[7]even though they may technically be mountains, as a Swiss person, I can’t call them like that
[8]for the video, look at the first day of the blogpost one more time