Ireland Camp 2023

From 26th of June to 2nd of July a team of four participants accompanied by Timon Stampfli and Jan Schär went to Ireland for an intense week of training.

Timon Stampfli

Sunday and Monday (Ferdinand)

Our trip began as we met at the airport, very excited for the week laying ahead of us. In typical SOI fashion, of course, this was already the first delay of the day. Luckily, however, the leaders had planned in enough time and the airport was surprisingly empty. After having swiftly passed through airport security, we decided to use our extra time wisely and buy some gifts (in the form of chocolate) for the Irish team. Unfortunately, there were too many good options, and we couldn’t arrive at a decision. As a solution, we tried the tactic of spontaneously asking some of the Irish leaders to make a selection for us. With this, we managed to narrow it down to two options. In typical Swiss manner, we did what we do best and ended the argument by democratic vote. After having bought the chocolate, we headed to the gate and spent the rest of the time with the first game of Tichu for the week. For the 2-hour flight itself, we didn’t really have any plans. So Mark and I, feeling overly optimistic, decided to download lots of tasks (including those from the Irish Olympiad) to solve on the flight. Completely unexpectedly, we didn’t nearly manage to solve all the tasks (we haven’t to this day, in fact). After we landed and managed to find some food, came the most amazing part of our voyage, the Air Coach bus ride from Dublin to Cork. For some reason, we failed to comprehend the fact that this part of the trip was even longer (namely, more than 3 hours) than the flight itself. We thought that this would only be a short final leg of the journey, but at least after the first hour on the bus, our tired selves started to realize the error in our belief. Accepting our fate, we decided to pass the time by looking out the window, chatting about lambda calculus, and sleeping. When we finally arrived in Cork, we were warmly greeted by some of the Irish organizers and accompanied to our dorm. We ended the day with some games (including Tichu) and went to sleep to be ready for the first day of camp.

On the next day, we got to meet all the other Irish participants and organizers. After a short introduction, the first lectures of the day began. The focus of this day was on graph algorithms (e.g. for finding articulation points) and some other small tricks that could be used to solve certain tasks. What I especially liked about the presentations was that they were always accompanied by interesting and challenging problems we could discuss and solve together. When it came around to implementing though, it began to become more frustrating, especially for me. I had the great idea of trying to implement a complex problem that I should have probably only solved theoretically. Although my efforts to debug my solution spanned the entire day, the grader was not to be persuaded into appreciating my efforts by accepting my solution. Instead, I was forced to continue my attempts on the next day. After heading out for lunch, we were given a tour of the university campus of UCC where we were located. Some of the highlights included a refurbished observatory from the 19th century and a church with many interesting stained-glass windows. Furthermore, we learned that superstitions play quite an important role in the everyday life of the students at the college. For example, there is the belief that if they walk on a certain grass field in front of the main building, they will fail their exams. Another superstition is that rubbing the nose of the statue of George Boole gives you good luck. After the interesting tour about the long history of the university, we headed back to our classrooms for some more lectures. After solving a few more problems, we also had the chance to try out the environment for the contest tomorrow. While the setup worked quite well for the others, I had some problems with getting my syntax highlighting to work. After troubleshooting for a little while, I decided to give up and hope that there wouldn’t be such problems during the contest (spoiler: there were problems). At the end of the first training day, we ended the afternoon with a few games together with some of the Irish participants. After playing for a bit, we realized that we were, in fact, quite hungry. Thanks to a recommendation from one of the Irish leaders, we found a nice Chinese restaurant (apparently, it was the nearest place to experience Irish cuisine: they had a Chinese dish called spice bag, which only exists in Ireland). As the options were quite extensive, we decided to share some dishes to try a bit of everything. After a filling dinner, we went back to our dorm and finished off the day with various games.

Tuesday (Hannah)

On Tuesday, we went on a Paddy Wagon tour of Cork. Our first stop was Blarney Castle. There is a superstition about a stone (the Blarney Stone) in the castle, that if you kiss it, you get the gift of the gab (the ability to talk with fluency and eloquence). Of course, we had to try this! Yet none of the participants actually wanted to volunteer. So, in traditional Swiss fashion, we decided with a game of rock paper scissors, that Mark should do it.

Irland Camp

We then left the castle because there was a lot more to explore. For example, the poison garden and the carnivore garden. Before entering the carnivore garden, there was a sign telling us that some plants may bite, so we should pay attention. Careful not to get eaten, we went in. There was a bee that wasn’t as careful as us, or maybe it just liked the adrenaline rush. It flew directly onto such a plant. Luckily, it managed to escape again. After visiting these gardens, we searched the map of the castle for what we should visit next and we saw that there is a cave. We looked for it and some of us even found it, but Mark, Ferdinand, and I got distracted by a little wooden house which was perfect to play Tichu in it. Sadly, because Théo was not with us to play Tichu in the Tichu house, we left again and reunited with the rest. They told us, that they had found the cave, but apparently, we hadn’t missed that much. Next, we found a playground with a swing that could swing in circles. It was great until we got dizzy and had to stop swinging. But as we then decided to play Set, it actually wasn’t that bad, because Set is great (I don’t think that the others agree with me). We then realized that we had to hurry to get back to our bus in time. We ran as fast as we could, but being a good runner does not help you when you forgot where you have to go. So despite giving our best, we arrived at the bus late. Luckily the bus hadn’t left yet.

Because the next stop was about an hour away, Timon gave us the task statements from the Irish selection contest of last year. Some of us managed to solve a few of them, whereas others slept. This was what I did during almost all of the bus rides. But Ferdinand, who was sitting next to me didn’t feel sleepy at all. He was debugging. Every time I asked him, he was very confident that it was just about to work. It did not work.

Our next stop was a fort right by the sea. We only had about half an hour to explore this stop, so we just walked around the fort and even managed to not be late for the bus.

It was time for lunch, so the bus driver drove us to Kinsale where we had about an hour to eat. There, a big task discussion started. During lunch, the tasks of Irish selection day 1 2022 were solved, so for our next bus ride, we could look at the tasks of day 2. But I didn’t, as I slept, and Ferdinand didn’t as he still wanted to debug his program.

The last stop was Cobh. This was the last stop of the Titanic before it embarked on the voyage where it sank. We didn’t go to see the Titanic, but we saw another cruise ship and got the idea of a cruise ship camp. Sadly, our leaders weren’t that fond of this idea. We also visited a cathedral, but we all were quite tired, so we went back to the bus early. This meant Ferdinand could debug again. When the bus was back at the starting point and we technically should have left to go home, Ferdinand was still sitting in the bus and debugging. We managed to convince him that he can also debug at the dorm (and the bus driver told him that he should leave) so we went back home.

During our discussion about our preferred dining location, there was a Ferdinand sitting on the couch, debugging. He actually said that he was confident that he could finish the task today. I’m not sure how many people believed him. After deciding where to eat (and separating Ferdinand and his laptop) we had dinner at a Mexican restaurant. Since it was quite late due to us taking a fair bit of time to decide where to eat (and especially getting Ferdinand away from his laptop), the restaurant told us they were closing now, before we even could decide whether to get ice cream. At least Ferdinand wasn’t that disappointed, as this meant that he could go back to debugging.

So, we went to the dorm and played some games (or debugged). Our games were interrupted by Ferdinand saying that he is submitting, and we all ran to his laptop to wait eagerly for the AC. It did not get an AC, so we went back to playing games. Until Ferdinand told us again that he is submitting. And this is the moment when the incredible happened. The task Ferdinand had been debugging for what I’m pretty sure were 10 hours, scored AC. “This is the best moment in my life”, he proclaimed and finally, Ferdinand could play games again without having his laptop in front of him and debugging.

Wednesday (Mark)

This was the first day of the IOI Selection for Ireland and after quickly eating breakfast we went to the computer lab to participate in the first contest. Some of us had some problems with setting up our PCs, especially IntelliSense on VS Code, but these problems were solved relatively quickly. We got three problems to solve in four hours. The easiest problem was a number theory problem about squarefree numbers, with quite a confusing statement, which was solved by most of the participants. We also had a tree dp problem, which after the solution presentation, each of us wished to had spent more time on it and solved it. The last, and probably hardest problem was a geometry problem. No one solved any of the two harder problems, which resulted in a rather small score distribution. This made the next day even more important for everyone.

We also had a minor scheduling issue, which was that our planned lunch was during the contest and since the cafeteria closes at some point, we had to take a break during the contest and “stop” thinking about the problems.

Since this contest was organized by the Irish leaders, we weren’t ready for the way they scored problems, as they didn’t have any subtasks, instead your score was just the percent of test cases that your program passed. At SOI we usually get subtasks where the more efficient your solution is, the more points you get, and a wrong solution would almost always score 0. In today’s contst, we could write a wrong solution that solves only some test cases and still get ~20 points per problem.

After the contest we had the solutions presented and then learned how to play Irish snap, an aggressive reaction card game with too many rules. We took it very seriously and Théo ended up getting a cut on his hand thanks to somebody’s nails. Afterwards we went to a pizza/burger place with part of the Irish team. In the evening they showed us the coolest attraction in Cork, a shaky bridge featured in a Tom Scott video. After bouncing together in a group of nine people in the middle, we can confirm that it does shake and is also very loud. In the evening we played some board games before going to bed too late again.

Irland Camp 2

Thursday (Mark)

The final day for IOI Selection started just like the first day except this time we were using the SOI grader and some of the problems had subtasks. We had a prefix sum problem, a hard graph problem and an easier graph problem, which was mostly just implementing an MST. The Swiss team performed quite well, as we all solved the prefix sum and the MST problem. The contest was also made shorter to be only three and a half hours to not get the same scheduling issue like yesterday.

After lunch, we had a talk about George Boole which ended up turning into a talk about the structure of jokes, which was still very interesting from a retired professor from UCC. After the lecture there was a Codeforces contest which we found out about 3 minutes after it started. Ferdinand and I participated in it, and both lost some rating due to our late start and some debugging. In the evening the leaders left us to go to a pub together and we decided to play games with a few of the Irish participants. We played some online games together (which was quite ironic considering we were sitting in the same room), such as gartic phone. Most of the prompts in gartic phone involved Ferdinand struggling with debugging his code or us struggling with other complicated topics.


On Friday, we went back to UCC for some lectures and attended the medal ceremony for the Irish participants. We first had a fun lecture given by Suneet on square root decomposition. Shortly after Suneet’s presentation, we had a talk by Professor Provan from UCC on greedy and randomized algorithms. After lunch and the medal ceremony we had a few more lectures on centroid decomposition, lowest common ancestor, and heavy-light decomposition with some challenging Codeforces problems. In the evening, we went out to play pool in Cork before heading to an Asian restaurant with a few of the Irish participants for our final dinner in Cork.

Saturday (Théo)

We made pancakes for breakfast, before participating in an AtCoder contest. We had lunch before heading to the train station to get to Dublin where we spent our last day in Ireland. Once in Dublin we checked into our hotel then went to a Chinese restaurant with really spicy food in which Ferdinand struggled (succeded [1]) to eat rice with chopsticks.

[1]I definitly succeded; it was only the rice not being sticky.

Sunday (Théo)

On Sunday, we ate a traditional Irish breakfast, then went to visit Dublin Castle’s garden and an art museum before walking by Dublin’s 120m steel spire and eating pasta at an Italian restaurant. After that we didn’t have much time left so we headed to the airport to get back home.

Overall we had a blast on this trip and learned useful new techniques. The Irish participants were also really fun to hang out and play games with. I hope fun and enriching experiences like this one will be available for future SOI participants.