Girlscamp 2025

Sunday, June 22nd (Myriam)

As on Saturday, we had a four hours contest in the morning, with sorted tasks. The first one was about eating as many cookies as possible (I think we can all understand this concept), the second one required us to find how many distinct sequences of memes we could create, the third one was about creating as small or as large numbers as possible in a game by adding every digit. The last (and hardest task) was a children game so a child may have more ideas to solve this task, you probably already tried it: you have three sticks and some circles of distinct sizes on them. You want to move all the circles on one stick, but you have an additional constraint (it wouldn’t be fun otherwise): on each stick, at any time, the circles have to be in decreasing order, and you can only move them one by one. In our task, you had to find the minimal number of moves, but there were queries that added some circles on one of the stick. Guess what everyone love during a contest? The answer is obviously finding an O(n log n) solution for the first task and getting random TLE on every subtask ($n ≤ 50, n ≤ 1000$ and $n ≤ 10^6$), then, after trying to debug your code, implementing O($n^2$) and O($n^3$) solutions, and still getting zero points because of TLE! (You don’t have any function (recursive or not) and no while loop either, only well-defined for loop.) Then, you obviously don’t want to apply any contest strategy, you only want to solve this task. You try, try again and you fail, fail again. You finally try some subtasks and finally solve one of them. The contest ends and you have a beautiful score of 13 points on one specific subtask, and still zero points on the first task.

Then, hungry and depressed, you go to lunch, you eat and you come back in the contest room for solution presentation. You learn that for the first task, some O(n log n) didn’t pass because of too big constant factors, but they still got 39 points. You realize that you have a different solution than the other participants, but you got TLE and not WA, you also discover that there exist a linear solution. The solution presentation then continues.

Then Hongjia left for Berlin because she was going to the Munich Camp for IMO training. She could have stay longer, but she didn’t want to assist to the beginning of the sponsor event. “Did I hear correctly? Sponsor event?” Well, yes. We first had to do human bubble sort [1]. They first asked us to sort ourselves by programming experience, then they realized that we just used our fingers to show numbers instead of talking, so they forbidden it. We then had to sort ourselves by shoe size, but half of the shoes had there size written on the sole and finally we sorted ourselves by hours of sleep the previous night but half of us had a smart watch and just showed the written number.

Then they formed groups with four-ish participants of different-ish countries. We had, step by step, to invent a solution for stress or decision-making issues, and to “build a prototype”. As you probably already realized, we all did an amazing job and not a single person on Earth is still stressed, and everyone is completely sure of what they want to do in the future.

At the end of the sponsor event, we received some merch, including a beautiful pencil with the amazing quote “Don’t worry about IT – be HPI”. (You should pronounce HPI as the German letter H and then pi, still in German.) We also received a rubber duck! 

After the end of the sponsor event, we ate dinner, and then Priska and Hannah wanted to talk with us and we discussed contest strategies and stress (sorry for this mistake, this doesn’t exist enymore) with them and Paulina. Then Hannah and me went debugging the first task of the day (yes, there wasn’t any time between the contest and then to do it). We looked at the first testcase that failed, which consisted of 25 test, with the O($n^2$) solution. Something strange happened: my code didn’t end and didn’t print anything! We tried to print-debug, and it appeared that my code was stuck in a for loop. But after even more debugging, we realized that my code printed correctly the first 20 tests, and was then stuck. But the test case had in reality 20 tests, and not 25, so my code was waiting for the end of the input. What should you remember from that? When you get a strange TLE, try to be even slower by not using fast input output anymore and then it may pass! Then the German leaders rejuged my submissions and it multiplied my score by 4! (Only by 4 because I had a too big constant factor.) After implementing the O($n$) solutions, I joined a group of leaders and participants and we talked and played games.

Monday, June 23rd (Zsófia)

Monday began with a shift from the usual solo contests, namely with a 4-hour group contest. We were divided into teams based on our performances in the two solo contests the days prior. While everyone had their own computers to read the tasks, only one person was allowed to code/debug at a time, which made communication and efficient planning essential. In the afternoon, we gathered again, like in the previous days, for a solution presentation, where all of the tasks were discussed, and their solutions presented. After that, we had time to socialize, play games and upsolve. Before upsolving, a few of us went for a walk to the Elbe River. On the way back, we stopped to visit the bears living next to our youth hostel and took some cute photos of them! The program for the evening was lightning talks, which are group presentations you have to prepare in only 30 minutes, about any topic. It can be serious, but usually the topics were silly. Some topics included:

• Why you should be late
• Why SBB and ÖBB are better than Deutsche Bahn (Yes, these two were topics of the same evening. Naturally, punctuality was an argument)
• Polish memes
• Leaders pronouncing difficult words in languages that aren’t their own. An example was:

[PL]: Ustawa o delegowaniu monitorowania etykietowania wołowiny

[EN]: Law for the delegation of monitoring beef labelling

[DE]: Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz

After this, the day ended with even more games.

Tuesday, June 24th (Myriam)

Tuesday was the five hours contest day, which means that we couldn’t eat lunch at the hostel, so we had to prepare lunch bags with sandwiches, bananas, apple juice, eggs, and so on. The contest consisted of four old SOI finals tasks. The first task was about a game where the goal is to light candle, but without using matches, that would be way to boring, so we had to use as less dragons as possible (the dragons lighted all the candles in a specific range). The second task was about organizing a programming tournament in order to rank the participants by their coding skills. The next task was called quantum grid, where there was a grid of particles and we had to connect while minimizing the cost. The task wasn’t especially hard to solve, but the statement was really confusing. The last task, U-Bahn, was about travel time optimization by constructing train stations. After the contest, Seraina, Laetitia, Zsófia and me went back to the hostel to eat outside on some chairs. Then, we had solution presentation, we tried to upsolve some tasks and we played games such as The Crew until and after dinner.

Wednesday, June 25th (Laetitia)

After breakfast, we had our final four-hour solo coding contest. Everyone was fully focused. You could hear only typing.

After lunch, we went over the problems. Since the organizers didn’t have time to review all the tasks, the participants explained the problems to each other. It was the easiest contest of the week, so the discussion was shorter than usual.

In the afternoon, we visited the swimming pool in Torgau. It was a bit smaller than expected. The outdoor area was closed, but we still had a good time indoors. The main pool was mostly used by older swimmers, so we stayed in the warmer kids’ pool, playing with a water ball (nicknamed: 57) and using the small slide.

After dinner, we played various games like Tichu and Bang. Some of us kept playing until morning. At 10 p.m., we ordered pizza and ate together to finish the week.

Thursday, June 26th (Seraina)

As usual, we got up at seven a.m. (at least the ones that actually went to bed) and ate breakfast. The breakfast was as always very good, especially compared to lunch and dinner. Unfortunately, the camp went by too fast and we already had to pack our stuff and clean the rooms. We then said goodbye to all the other participants and leaders, before we went to the train station. On the way, we grabbed some lunch at Aldi and were really surprised by how cheap it was (only 24 Euros for 6 people). In the train we obviously played some games, like the “stupid German game” (at least according to Paulina) and made a loooot of progress with our blog posts. Hannah, Myriam and I also discussed English grammar, as we didn’t agree whether it was “the earlier the better” or “the earliest the best”. In contrast to the travel to Torgau, on the way back, the Deutsche Bahn lived up to its reputation. The first three trains were up to thirty minutes late, which led to us stranding in Basel Baden, because the train could not enter Switzerland anymore. Luckily, after some unusual physical exercise, aka running, we were able to catch the next few trains and eventually arrived in Zürich. There it was already time to say goodbye. Overall, we spent a great week at the girls’ camp, did many fun and interesting contents and enjoyed playing games with the other participants from Germany, Poland and Austria. Thank you to the leaders for making this camp possible!