Slovak Camp 2025
We were invited by the Slovakian Olympiad in Informatics to join their IOI selection from 3 May until May 10th. The Swiss delegation consisted of Yuhua Su, Ursus Wigger, Linus VandeVondele and Myriam Faltin accompanied by Ferdinand Ornskov and Hannah Oss.
The impressions of the camp are collected below.
Thursday, 1 May (Myriam)
We [1] first met in Zurich HB at around 20:30 (some of us had to leave earlier than others to get there in time [2]). Then we took the night train to Vienna, it was nice: we had a compartment for ourselves and we played some rounds of Tichu. But we unfortunately had to change train and then weren’t as lucky anymore for the rest of the travel (there were other people which meant it was more cramped but who needs sleep anyways). We thought a little bit about some informatics problems and I think the best adjective to describe the night is short. At least Ferdinand definitely didn’t have any laptop battery issues…
We arrived in Vienna around 07:00, left our suitcases (we didn’t lose any of them) in the train station, went to the city center and searched for a place to eat breakfast. Unfortunately, on 1st May, it’s easier to find a demonstration than a place to eat. We finally ate croissants in Starbucks, and then we succeeded going to the Opera house without being in the middle of the demonstration. Then we went to some emblematic places in Vienna: the Schweizer Tower and the Schweizer Hof, where we had the great honor to be in presence of one of its creators: the Kaiser Ferdinand!
We went to some less important places in Vienna as well, such as the Parliament, or the cathedral. One of this building had some Latin numbers written on it, but we didn’t understand them: we don’t do the cryptography or the linguistics Olympiads after all!
Ferdinand and Linus wanted to eat Wiener Schnitzel for lunch, so we went to another typical Austrian place: the Schweizer Haus. I think they appreciated the air bubbles. Hannah had pasta with poppy and she made her family SO JEALOUS!
We obviously did a few tichu breaks during the day, including a lot of warm-up rounds if you listen to a one of the teams. Then we went to a castle and did some historical reconstruction:
Then we came back to the train station, tried to buy train tickets and went to Bratislava. When we arrived in Bratislava, we went to the hotel and after some language issues, we finally got into our rooms around 19:30. Then we searched for a restaurant and founded an Sushi restaurant. We arrived around 20:30 and the restaurant closed at 21:00, but we managed. I took some noodles with tofu and peanut sauce. Ferdinand, Linus and Hannah took sushi. Hannah’s ones were amazing, and they were even vegan! She made her family SO JAELOUS!
| [1] | Linus, Hannah, Ferdinand and I |
| [2] | between ~10:45 and ~20:00 (guess who was on the 10:45 side…) |
Friday, 2 May (Linus)
After having a really good night’s rest in the hotel, we wanted to spend some time in the old town of Bratislava. But first we had a good breakfast in the canteen, even though we had not booked it for this day. Hannah and Myriam had pancakes with Nutella and Ferdinand, and Linus had eggs (scrambled or with ham).
The old town of Bratislava had many beautiful buildings and many statues.
For lunch we had traditional Slovakian food. Myriam and Linus shared 3 different local dishes (see picture below). Ferdinand had a big loaf of bread with a cheese soup inside. Hannah had a special kind of pierogi.
What would a SOI event be without playing Tichu? Yes indeed, we sat down in a park and played Tichu for many hours. For dinner we went to an Italian restaurant. Unfortunately, they only had pizza that night, but it was still tasty.
Saturday, 3 May (Jason)
The journey began around 8 p.m. at Zurich HB station. I was looking for Ursus, who’d already been waiting for a while. To my surprise, Mark was there too, but it turned out he just happened to be nearby and wasn’t joining us for Slovakia. We walked through carriage after carriage until we reached our compartment which claimed to have enough space to house 6 people. Around a few minutes before departure, the compartment held just Ursus and me — plus Mark, who was chatting with us. We prayed no one else would show up. When departure time arrived, Mark still hadn’t gotten off, but the train was delayed. Then, my hanging heart was finally — dead, when, at the very last second, several men squeezed into our compartment. Mark managed to hop off with two minutes to spare — I almost felt sorry he didn’t get taken away to Vienna by accident.
There are quite a few fitting descriptions of the journey with the night train but “best-sleep-ever” certainly isn’t one of them. Throughout the night, echoes of “uncomfortable” and “cramped” filled the cabin — though perhaps only in our dreams. Ursus and I lay across from each other, and only IOI-gold-medal-level memory-allocation skills could let us find any comfortable resting position. We glanced at the daily task, then decided to try to sleep — though we only barely managed to.
Come morning, we got off and grabbed breakfast. I discovered egg in a sandwich labeled “Vegan”, didn’t know if it’s still qualified. Next up was a train from Vienna to Bratislava. We finished the next day’s daily task during the ride, then took a bus to our final hotel. While transferring, we got stuck in an elevator. Then we tried Schindler, and it worked eventually.
After meeting the rest of the group, we chose a local restaurant near the university for lunch. During the meal, Ursus randomly pulled out his Tichu deck… to play “24” (making a target number with +, –, ×, ÷, etc.). None of us realized this would become the camp’s most popular game, and Tichu itself barely got played afterward. That day we allowed only basic operations like square root and factorial. Later we’d add all sorts of bitwise tricks. Linus was just incredibly good at this game.
The afternoon contest problems were still reasonable (compared with what would appear later). Dinner was fairly ordinary (compared with the coming feasts). And we went to bed early (compared with the next few nights).
Sunday, May the 4th (ft. Ursus and bread sauce)
Getting up
What a fantastic sleep!
The four of us (Myriam, Jason, Hannah, Ursus) only slept around 5 to 6 hours, but I finally had a normal non-train bed and it was such a good sleep!
Well whatever, let’s get down to the breakfast. I remember that we had a whole sortiment of breakfast articles which we can choose from last year, but this year, we could order nutella pancakes with berry sauce. It also seems the communication was much easier than last year, so that’s an up!
The Breakfast
The pancake, though simple in ingredients (pancakes, nutella and berries), is a fantastic and sweet breakfast giving you enough sugar in the day. As a professional cereal-eater, I don’t really like a non-cereal breakfast. But this, I could eat this every day [3].
Overall: 10/10
Pre Noon
Our daily walk began, from our hotel to our contest room. I know I’ll see that walk a lot, as we will have - foreshadowing - a total of 45 hours of contest this week. Yesterdays task were hard, but they will hopefully be a bit more approachable.
But today we didn’t do the Slovak contest, but the ACTS contest from jetbrains. That contest had 5 tasks where you don’t even need experience in CP to solve them (but are easily fakesolvable because the first two are just annoying case bashing). The last 2 were nice tasks, though not all had the time to solve them after implementing the first 5.
Well whatever, everyone of us solved the easy tasks (except Jason who didn’t see an edge case on the first task, I also almost didn’t see that one). So, let’s get - all the way back to the mensa - to our lunch!
Lunch
What was this? Some pasta with sweet sauce? A ‘lil bacon? I wasn’t a great fan of it but it seemed that everyone else wasn’t either.
5/10
Afternoon
We took our walk [4] back to the contest room and we were ready to start the real contest now. So, I hated those tasks so let’s rant about them now:
- First, there was an interactive task about shuffled encoding/decoding. You can get subtasks but it was hard to get all the points.
- You’ve got an geometry task where you have to count points between areas of line segments. I had no idea here (and about geometry anyways) so I looked at the next task…
… and the next task was a big… (well, what’s the most appropriate word here)… a big pile of horseshit.
You got triangles and squares on a line. Find the length of the convex countour. Sure, that’s not bad, but then there were also circles… and then you see the edge case where you have to find the tangent of the circle to match the contour because of triangles.
It’s just some trigonometry, but implementing this thing correctly was the most annoying and time consuming thing ever. And the task wasn’t hard so ach, this was so annoying.
Well, at least it’s over now so surely there won’t be…
The name of the gas station next to our hotel
Oh…
Oh no! It’s everywhere!!! No!! How can this be?! This task will become a nightmare!
Can’t it just stop?
Ach… much better!
Dinner
Soon after, we went to the Sushi restaurant where Ferdinand, Hannah, Linus, and Myriam already went to. I heard there was good vegan Sushi, which first sounded like an oxymoron, but was pretty good!
I tried a bit from their special SOI-sauce, and if I’m being honest: That sauce tasted like bread. I don’t know why everyone laughed but it really tasted like bread. And with several difficulties using chop-sticks (I’m still better than Mark), I was able to eat this delicious Sushi with SOI-sauce. There were also some pictures of me cutting Sushi with sticks [5].
Overall: 9/10 (+1 Hannah Bonus (+2 Bread bonus))
Ach, surely you are jealous of how good the food was, here are some pictures of the food to make you even more jealous [6]:
Evening
On the way back, we told each other different proverbs from german and french. Maybe the people should write behind their ears that SOI-sauce tastes like bread, although it’s comparing apples with pears.
Anyways, we went back, I tried to solve the daily task (which was very realistic by the way, the rules resembled reality quite accurate), but I prefered to play some games.
The trio assembled again: Me, Jason, and Myriam to play play all the different games Myriam brought. Me and Jason learnt that new game called Twint [7] which is like Set combined with memory, and a lot of patterns. Ferdinand also came at some point to play games… and continued the entire night to work on his laptop. So, we played exploding kittens with for 10 players with 3 players. But actually, we went to bäd bed quite early.
Let’s see what awaits us tomorrow!
| [3] |
| [4] | Getting tired already? |
| [5] | Don’t look at the flickr! |
| [6] | Imagine something like this in SOI camps. |
| [7] | (Someone named Myriam will hate me now, but she does it anyways so lalala) |
Monday, 5 May (Linus)
As nearly every day, for breakfast we had pancakes with Nutella. The first 3 hour contest in the morning consisted of 3 different tasks, one geometry and graph theory task (what a surprise), a 2-SAT problem and an easier adhoc task (congratulation to Ursus for being first place in this contest).
After eating lunch with the Slovak delegation, the 4 hour long afternoon contest had a simple greedy task, a not impossible second task and an impossible third task, where non of the participants got more than half of the points (congratulation to Json for being first place in this contest).
For dinner we went into a Chinese restaurant called Jasmin next to the old town. Like the other days the food fas great.
Tuesday, 6 May (Ursus)
Breakfast
Another day, the same procedure.
Getting up, go to mensa with those delicious pancakes, and all the way to the contest room. Today was only a contest in the morning, so no afternoon contest but some “free afternoon” program. We will see what’s then.
Contest
Before we started the contest, I realised that I brought some Swiss chocolate to distribute with me, so Myriam took some of them and shot them at people’s head’s with a force comparable to throwing rocks.
But well, let’s solve some tasks. We got two tasks this morning:
- Finally! A nice segment tree task!
- Literally, a trash task which was - figuratively - a trash task. I didn’t see the greedy which was sad.
Jason and Linus got full score on that contest though, congrats!
Lunch
Uhhh, what was it again? The typical meat with rice dish? Yeah, it’s serviceable.
Overall: 7/10
Afternoon
Jason needed to work something so he went back to the hotel, while I now write this entire blog post because of that.
We just followed one of the Slovak leaders to the place. I overheard some Slovak participants talking about the best chocolate being a specific Slovak chocolate… Dear reader, please have patience with those children, they’re still young, they still have a long life before them, so it’s just in their uneducated nature to spread words like that.
We gave them Swiss chocolates this morning, but this is only the tip of our chocolate cultu… (okay, maybe let’s write about the actual afternoon)
So, it appeared that we went to a place from Vincet to play games, which sure is nice. It was in a skyscraper so we had nice view up there. We invented some SOI tasks for the future generations of partipants along the way, but upstairs, we played a lot of games.
We started with Hanabi, some exploding Kittens, another group played DnD and we had fun! I also improved the F++ [8]. The compiler thinks Hannah is a minor [9], so it sometimes refuses to work properly.
But then, we got told there is a game room downstairs with billiard and table soccers, so we went downstairs. It was there yes, BUT THERE WAS ALSO A VR HEADSET. The headset’s battery was depleted, so we first had to recharge it. In the meantime, we played table soccers. Me, Ferdinand, Hannah, and Myriam first played an extravagant round of “Boys vs Girls” and the boys won eZ. Then we switched to “participants vs leaders” and the participants won eZ [10]. We even r3kd the leaders with a completely unergonomic setup, so l2p n0bs.
Okay, at some point we played with 12 footballs so we decided to stop right there and go check the VR headset. It somewhat charged (we still attached it to the power bank), but it was working! (nice) It was a Meta Quest apparently because I saw my horrid avatar. Else, I was mesmerised by the thing actually working and all the VR stuff, it’s always cool! Surely, nothing bad happened while I looked like an alien…?
… ach! So for protest, let’s put some pictures of you two here:
Sadly, we had to leave soon, so we went to a place where we can eat.
Dinner
Jason found his dinner by himself so we just went to the Vapiano just next to us. The location we currently were at was surprisingly modern, it looked way too fancy.
The food: I got a vegan Margharita, some people got pasta, classic food for classic taste. But to make you even more jealous of the food: I made a picture of Hannah taking a picture while Ferdinand took a picture of me taking a photo of Hannah. Now, if Hannah’s photo is 1 times jealous, then Ferdinand’s picture is 3 times the jealous!
Ha, cry about your bad dinner your currently eating, we had the best food here! Okay, but to end this subchapter with some real words: The food was nice, you can always eat it.
Overall: 8/10
Evening
We went back to find Jason in his room. Myriam managed upsolve the daily task, and so we played another evening a bunch of different games.
| [8] | You may want to read the RMI 2024 blog for more infos |
| [9] | I mean, I see why. |
| [10] | Now find the union of the winner sets… (that must have been the worst weird flex ever) |
Wednesday, 7 May (Jason)
Breakfast today was ham and eggs. Because three or four fried eggs had stuck together, the moment I cut into them yolk started leaking everywhere.
The contest problem set came from the SOI leaders today, and suddenly every task just felt so much more approachable. Still, the fact that nobody managed a full score left even the Slovaks a bit stunned.
In the evening we played board games. In one of them, we took turns giving a hint; everyone picked a card from their hand that matched the hint, we shuffled the chosen cards, and then tried to guess which one was the hint-giver’s original card.
So the hint was: “Ursus.”
Each had its own ridiculous explanation. For the answer please contact Ursus himself.
Thursday, 8 May (Jason)
It’s another bright morning. For some reason, since I bought an umbrella it hasn’t rained once in Bratislava.
At breakfast everyone ordered the exact same thing again—a pancake drenched in blueberry jam—then filled their cups with sparkling water from the dispenser; honestly, I started to like the composition.
That number-summing game has now broken into three-digit territory. Someday I’m definitely going to write a DP to cheat.
The contest problems were classic Slovak fare once more: intimidating greedy algorithms and computational geometry. When it was over we headed downtown. Even though it was a Thursday night, the place was buzzing. For dinner Hannah and Ursus had pasta in a black sauce topped with a single strawberry—maybe meant to look like a volcano. I went back and slept early, since I had to catch a 9-a.m. flight out of Vienna the next morning (which ended up being delayed by more than three hours)
Friday, 9 May (Ursus)
Breakfast
After getting up from a healthy… - okay, I should clarify that roughly 2h of sleep is not something one should normally do. Especially if one spends 7h of writing a contest that day. - Anyways, where was I again?
Ah, yes! After getting up from the power nap, I realised that Jason already made his way to Zurich. I hope he will successful at the maths olympiad.
The rest of us continued with the basic procedure: Breakfast at the mensa (with those delicious pancakes) and up we go to the contest room. Some of us [11] already felt the impact of our short night while walking to the contest room. But that didn’t stop us of writing a good contest… or did it?
Contest
The morning contest started with two tasks:
- Some where you have to multiply and sell horses.
- One where you have to make a big tank and check for reachability.
The horses task was okayish, but well, what was the second task?! It starts as a grid task, but without spoiling here, it gets really interesting really fast! I tried to get the points on that task - unsuccessfully - but it’s a great task, especially implemention-wise. I was too tired to actually get subtasks here, so my number of points were an all time low.
So yes, the nap stopped at least me.
Lunch
We continued to go back down. We had a lot of nice discussions on the way about the tasks. Back at the mensa, we got another meat with something dish.
Overall 7/10
Second contest
We were greeted with three tasks each worth of 27 points:
- An ugly combinatorics task (it’s the embodiment of ugly tasks).
- An interactive task, an easy solution, but hard to find.
- An task where you press the up and down volume of an mp3 player.
The final of which is an interesting task if I do say so myself. I solved the interactive one, where Linus and Myriam had a lot of partials over all tasks.
Dinner?
As normal, after the second contest, we made our way to find dinner. We already planned to go to the Sushi place again with the phenomenal bread sauce, I would’ve liked to eat that again… I use the irreal tense here because I also had to leave sadly.
I had to return to Zurich to participate in robotics… Ach, why did I participate there again? [12]
At least Ferdinand was so kind enough to pack my stuff in my room during the contest [13]. He also handled everything so I can leave as soon as possible.
Thus, I reached at my final moments of the camp:
Me: Okay, let me grab my stuff. It was cool here. Everyone goes down to the tram station. Me: Ach, kinda sad that I have to go now, but we’ll see us at team selection! We made some final jokes together, then the tram arrived which I had to take. Me: Allright, it’s time, see ya! Everyone*: Byeee, get home safe! Myriam: GUTEEE REIIIIIISçEEEEEEEEEE!!!!
The beginning of the end
I took the same route back as I took to get to Bratislava. I got a sandwich in the busy supermarket at the Vienna train station (I think everyone who was there knows which store I’m referring to).
And then I took the night train back to Zurich. At least I had only 3 other guests in the cabin. I was actually able to sleep well that night (the “power nap” from this day also contributed I think).
And now, I have to say goodbye. There is a blog for tomorrow, so I that person will have to write a decent ending. But that’s it, it was fun, anytime again!
…
Who actually writes for tomorrow? (Looks up the list…) Ach, Myriam? Woe betide you if you just write: “… and then we went said goodbye and that’s the end.”
| [11] | That is equals to everyone except Linus |
| [12] | At least it was not unsuccessful. |
| [13] | He even folded my clothes nicely, how fancy!! |
Saturday, 10 May (Myriam)
It was the second day when we didn’t have breakfast at the hotel, but we saved some Nutella and jam and kept a knife from the last time and we already bought a bread. We just had some cleaning knife efficiently issues [14]. Then we went to the university where there was a big duck meeting [15]
For the contest, we only had two tasks: the first one was about plane safety and pilot’s experience, but it was just an easy graph task with low limits so we thought it would be something harder. The second task was about torus, but it was apparently in reality a string task [16]. Then we had the solution presentation, the reveal of the final ranking, and a short speech from one of the Slovak leaders. Then we ate lunch in the hotel and met Ferdinand, who bought a frisbee as a thank-you gift for the Slovak leaders, and we all [17] signed it. Then we gave it [18] and we spoke with Slovak leader/participants about informatics competitions. After that we worked a little bit on our owns and played exploding kittens [19]. Then we went to the city center, ate pizzas, and took the train to Vienna, and then the night train back to Zurich (the sleep wasn’t even that bad but maybe we were all just too tired to be bothered). And then we went said goodbye and that’s the end.
| [14] | Alternating Nutella and jam isn’t the best idea when you want to clean the knife at each change |
| [15] | Ursus even left his so they could make new friends |
| [16] | No guarantee, I didn’t even understand the full solution |
| [17] | Ferdinand, Hannah, Linus, Jason (aka Linus), Ursus (aka Linus) and I |
| [18] | and the Nutella and the Jam that we still had |
| [19] | Linus never played it before! |