BOI 2025 Blog

Thursday, 25th September (Albert)

Our journey to the BOI started from two different locations. For me and all the leaders, it started at the main train station in Zürich but Andrej and Myriam left from the train station in Geneva. After 3.5 or 4.5 hours of travel, we finally met each other in Milan. Up until now, not much happened. Myriam mentioned they tried playing Tichu, but apparently, a 4-player game isn’t that much fun with just 2 people. We, on the other hand, were four people, so we played Tichu as intended for a long time. Then we decided to make it a bit more interesting, by letting the winner of each round create a new rule.

These new rules included:

• Every double is stronger than a single card, and triples are
• stronger than doubles. This means, that you can put doubles/triple
• whenever you want on singles/doubles. Every 6 changes the
• direction. If two or more rules would be applied by someone’s turn,
• none of the rules apply. (double rule) If you play doubles, the 2 is
• now the highest and aces are the lowest (because of the double rule,
• the 6 is now the strongest)

This got more and more similar to a different game called Crazy Time, which Ursus and I like, but some others really don’t. During the whole BOI, we were never able to convince the others to play it.

In Milan, we tried searching for a place to eat lunch at, which didn’t seem too suspicious. We were partially successful.

On the train from Milan to Udine we played games for another four hours. After 9 hours of travel, we finally arrived in Udine, where we got picked up by a minibus. On the last part of the journey, we had some conversations about the cars, because Udine felt like a mix between Western Europe and the Balkans. In the end, we concluded that it was closer to Western Europe than to Eastern Europe, and that “governments should try making people not die” (this was about safety in cars). At the hotel, after checking in, we all went into our rooms, and the day basically ended.

Friday, 26th September (Myriam)

On Friday, we woke up after a good night of sleep. After eating breakfast and getting our badges and goodies (only a tote bag and a t-shirt for the contestants), we went to the center of the city for the opening ceremony. The ceremony was great: it started on time, and the speeches were short (Luca’s speech was literally one sentence!) so we actually finished in advance! During the ceremony, we saw two videos: the first one that listed all past BOI editions (This year’s was the 32nd one, such a great number!) and the second one presented the different delegations, showing, for each country, the leaders first, then the participants, and finally the guests (so everyone was looking at a big picture of Ursus for a few seconds). After the ceremony, we took group pictures and we walked a bit in Udine before going for the first time to the Fondazione Renati for lunch, a great place where we ate five times in the week! There we could have bread, pasta with sauce, a plate with two things we could choose like beans, kind of crêpes, strange potatoes, suspicious meat, … and a vanilla or chocolate cream.

Then we went to a high school for the practice. Where do you think this could take place in a high school? Maybe they have a big auditorium? The gymnasium? Could we get dispatched into small classrooms? Well, if you think that, then you’re wrong! In fact, the contest room had planes in it! Also, they put flags of all participating countries (and Turkmenistan for some reason) and this was the most rectangular Swiss flag I have ever seen!

Now the important question: What is the objective of a practice contest? Checking that everything is working and allowing the participants to get used to the environment, to try to submit every possible kind of answer and to know exactly how every kind of task is presented. The two most current tasks are I believe addition and a binary search as an interactive task. This time, we got some of the tasks of the Italian selections that took place right before in Udine. There was one interactive task and the others were batched. But, in the contest, instead of having at least one interactive task, we got one output-only task each day. After the practice, we went to the Fondazione Renati for dinner and then back to the hotel.

Saturday, 27th September (Andrej)

BREAKING NEWS: Andrej finally finished his blog post!

Sunday, 28th September (Myriam)

Sunday was the excursion day, and we first took a coach for Trieste, a city on the coast of the Adriatic Sea and only a few kilometers away from Slovenia. Fun fact, Andrej told us that in 2023, the last time Switzerland went to BOI, which was in Slovenia, the excursion was also really close to the border with Italy. The great thing about the trip, which lasted a few hours, is that we were able to sleep and play stop the bus with categories like programming languages, what could go wrong in a contest (which are often the same), Olympiad brain rots (it goes fast with angry imp, sobbing imp, happy imp, smiling imp, crying imp, …) In Trieste, we could have audio guides and then visit the city for a few hours and then meet to take the coach. But we lost the group for the audio guides, so we just went on our own. There was also some kind of science fair that day, and the color of their t-shirts was the exact same one that for the contestants! We went on a hill to have a better view and tried to go to the castle, but the road was closed. We also saw a strange triangle on the mountain, and we wondered what it was. When we went back to the meeting point, well the buses just weren’t there, and we had to wait for them. Once they arrived, we went to this strange triangle, which was a church, and they had a restaurant that we expected fancy but that was really the same standings as Fondazione Renati. After eating, we went outside to look at the beautiful view of Trieste.

Then we took the coach to Grado, which is also on the Adriatic coast. They told us we had 30 minutes to visit Grado, which is really little. We tried to get ice cream, but right before we got them, a guide came to us and told us that we had to go somewhere because BOI bought guided tour of Grado. Then we joined the president of the Italian association for informatics, who was basically our guide for the tour, with him speaking Italian and the other guide translating. Then, we went to the meeting points for the buses, which were again late! This was unacceptable!

“Waiting for transportation is a typical Italian experience.”

BOI organizer

We waited for the buses longer than we were in Grado! And because we were already really late, we just didn’t go to the third part of the excursion at all. For dinner, we got pizza at the hotel, but there just weren’t enough pizzas for everyone (which is understandable when you know that the pizzas were only ordered half an hour before). Also, who can make such pizzas in Italy???

Monday, 29th September (Albert)

On the second contest day, we all woke up successfully before 8 am and got ready to leave on the bus after eating breakfast. Then, some organizers called each team one by one to get on the bus, checking if they were complete. For some reason, after they were finished reading off the teams, we were still standing there. First, they tried telling us that guests weren’t allowed to go with the contestants. But after telling them that we were contestants, and they’d simply forgotten the Swiss team, they let us join the others on the bus.

When we arrived at the contest hall, not much happened. We had to wait, so we played Tichu on the floor. There wasn’t anything surprising during the contest. It’s just 5 hours trying to solve tasks, so it won’t really be eventful for non-contestants. The contest hall was very nice after all, since there were planes and helicopters all around us. Even though, I liked the tasks much better than on the first day, there was a task, which all of us from Switzerland managed to misread for the bigger part of the contest. After the contest, we met our leaders and went to that school, where we got a kind of fancy Apéro. Then, we went back to our hotel without the leaders, since they had to go to the General Assembly.

At the hotel, we did stuff for ourselves for a few hours, until we decided to play games. In the evening, we once again ate dinner at the canteen, which was called a restaurant. Luckily, it’s basically impossible to be anywhere with the SOI and not have Tichu cards within an arm’s reach. This meant, that once we were all finished, we played a game where you pull a few cards and try to get to a randomly specified number using mathematical and informatics operations (like summing two numbers or bit-shift in binary). Later in the evening, we played Codenames for a few hours before going to bed.

Tuesday, 30th September (Andrej)

Yeah sorry for the last one. This time it’s actually the blog post

Wednesday, 1st October (Ursus)

After a short night, we had to get up and immediately go to the bus. The bus ride was rather short and not noteworthy. We just went to the train station where we had 2 hours left to do whatever we want. Since the ride from Udine to Switzerland is around 8 hours… well, it would be a perfect idea to buy food right there and eat it in the train. So, we went to the store nearby to buy some food. We wanted to have some nice sandwiches, but the ones which were in the shop… well, the bread didn’t look real, so we considered it’s not Hannah-safe, and we instead bought a bag pack-sized sack full of croissants… Hey, the price was only one euro! (Unlike the bread sticks, it actually tasted like that price.)

After that, we went to the train station and played Tichu until our train arrived. The train ride was very productive, everyone wrote their blog posts were solving tasks from the second round of SOI (which is currently available at https://soi.ch/contests/2026/round2/overview/, go solve it now). I also improved my personal best to 1:46:25 in the best game of all time. So yes, very productive train ride.

We arrived at Milano after a long train ride. There, we ate our final meal together at a restaurant there. We had a nice view on the train station and some decent food.

We quickly had to catch our connection to Zurich and Geneva. On the train to Zurich, we continued to do very big-brain and smol-brain moves in the game of Hanabi. One example of a smol-brain move was: “Okay, I give a tip: This card is yellow.” (while pointing at a completely white card). Yeah, we were tired, but this made it extremely hilarious and fun. At some point, we arrived at Zurich. And then we went said goodbye and that’s the end.