# Young mathematicians uphold Leiden's honour at international programming contest

Three young MI students have upheld Leiden's honour in the finals of the International Collegiate Programming Contest (ICPC). PhD candidate Ludo Pulles and Master's student Reinier Schmiermann travelled to Russia and came 15th out of 117 teams. PhD candidate Pim Spelier participated in the online contest and finished tenth out of 57 teams.

During the competition, each team gets five hours to solve twelve problems. Therefore, they have to write fast code: code that can calculate an answer within a few seconds. For example, the participants had to write a computer programme that could win at least 85% of the card games it played. Coach Daan van Gent says that this challenge remained exciting until the very end: 'One minute before the end of the competition, Pim was able to solve this problem just in time, amidst loud cheers of "85.16!". Just above the required 85%.'

In general, most teams only solve three or four problems. In order to make a distinction, the final score therefore also depends on how quickly the team finds its solutions and on how many incorrect solutions the team has submitted.

## Impressive scores in the qualification

The ICPC is a programming competition for students. The competition consists of several rounds: university, national (in this case Benelux), continental (North-West Europe) and international; the world final. In 2019, the Leiden team came first in the university national and continental competition. During the national competition, the team even achieved a perfect score.

### Dutch cooperation

Due to corona, the world final was postponed until 5 October 2021. Two of the participants are therefore no longer students, but have started their PhD studies. According to the original plan, the final took place in Russia. However, participants could choose whether they wanted to travel to Russia or participate online. Because not the entire Leiden team went to Russia, two new teams were formed in cooperation with the Utrecht team, which came third in the continental competition, so that everyone could still participate.

Ludo and Reinier formed a team together with the Utrecht student Jorke de Vlas. Pim was the only Leiden mathematician in a Utrecht team with Mike de Vries and Freek Henstra. Both teams were coached by former participants and finalists Daan van Gent (Leiden University) and Ragnar Groot-Koerkamp (Utrecht University).

## Back to battle

Ludo is positive about his experience in Russia. 'It was great to be together again with people from all over the world with a shared interest in competitive programming. We went in without much expectation; it was already good that we had qualified. This result is better than we expected!'

Headerphoto: Reinier (left), Ludo (middle) and Jorke during the finals in Rusland.