Victory at 24h de l’Info in Lyon

On Friday and Saturday, May 23-24, 2025, we participated in the 24h de l’Info in Lyon, a programming competition that brings together Computer Science IUT students from all over France.

This competition is divided into 3 events of 8 hours each: a first algorithmic/programming event where we solve a set of problems. Then a web development event where we must create a web application according to a fairly free subject. Finally, a Cybersecurity event where we must solve computer security challenges in the form of CTF (Capture The Flag), a popular competition format in the cybersecurity field.

Our team consisted of 4 students from IUT de La Rochelle Data/AI Developer track in Niort: Ivan Sabourin, Rémi Neveu, Kirill Petrov and myself. The goal was to form a team that complements each other well on the different events of the competition. For example, Ivan, Rémi and I are particularly comfortable with algorithms with the various programming competitions we have already done, while Kirill and Ivan have more knowledge in web development, and finally I have more experience in cybersecurity.

To prepare ourselves as well as possible for the events, we initiated a complete technical stack for the Web event, with automatic deployment, dockerization, etc. But having little knowledge in Cybersecurity, we called on a friend, a former IUT student, Hugo who gave us weekly 30-minute sessions for 8 weeks before the competition, to present us with the different types of challenges we would encounter, the tools and techniques to use, as well as the methodology to adopt.

The first event therefore begins at 2 p.m. and lasts until 10 p.m. A list of 10 problems was given to us and we could submit our solutions at any time, without knowing if our answer was correct or not. We managed to solve almost all the problems thanks to good work distribution, and after 4 hours we had already submitted an answer with 9 solutions out of 10 challenges, for which we were almost sure we had the right answer. We also tried to do the 10th challenge, but given the difficulty of the latter, we decided to keep our submission with 9 probably solved problems, to guarantee a good place because if two teams have the same number of problems solved, it’s the team that submitted first that is ranked ahead.

The team during the algorithmic event

Then begins at 10 p.m. the web event which lasts until 6 a.m. The subject of this year was “Lyon and its lights”, a fairly broad subject, but which allowed us in just 30 minutes to determine what we were going to do: a dark map of Lyon with points of interest that must be “activated” to gradually light up the city. With the idea in mind, Kirill and Ivan took care of the Frontend part, while Rémi and I collected all the points of interest to display. We worked efficiently with a clear idea in mind, which allowed us to finish the event at 4 a.m., leaving us 2 hours of rest before the Cybersecurity event.

Our site for the web event

Then begins the Cybersecurity event at 6 a.m., which lasts until 2 p.m., it’s the most difficult event, both because of the difficulty of the subject, but also because of the accumulated fatigue. So we all launched together, and the first two hours didn’t reward us much since we were then in 33rd place out of 39 teams. Nevertheless, we continued to work and no one gave up; little by little we started to solve challenges and climb the ranking progressively until reaching the top 10 around 10 a.m. then the top 5 at 11 a.m. The preparation we had done with Hugo allowed us all to work on challenges, and our endurance allowed us to always continue as 4 throughout the event.

In the end, our strategy for the algorithmic event which consisted of keeping a submission with 9 problems solved quickly proved to be paying off since it allowed us to obtain 1st place in this event. Nevertheless, we were disappointed with the web event where we finished in 22nd place, but we were still very happy and satisfied with the site we had created. Finally, our resilience in the Cybersecurity event allowed us to finish in 2nd place, which gave us 1st place in the overall competition ranking!

The team on the podium. From left to right: Kirill, Ivan, Nicolas, Rémi

It was a very beautiful team experience, our determination and our complementarity allowed us to win this competition brilliantly. It’s also a symbolic victory since it was our last competition together before the end of our BUT, and finishing on such a victory is a beautiful way to close these last 3 years.

A big thank you to my team, to Hugo for his precious help, as well as to the entire event organization!