A baursak week

The ICPC World Finals 2024 in Astana was the main event of this week (problems, results, top 12 on the left, broadcast recording, our stream recording). On our stream things did not go very well, as we struggled a lot getting problems accepted (only one + out of 9), so after getting 4 problems in the last 70 minutes including one in the last minute, we arrived at 9 problems with the penalty of 2238, which would give us a clear first place in the contest based on penalty time only :) With the usual scoring, it would only be enough for a silver medal.

Among the people born in the 21st century, the Peking University team was very fast on the easier problems, had very few incorrect attempts, in the end earning the championship title with a huge margin of almost 300 penalty minutes. Big congratulations to them and to all medalists! And of course huge thanks to all #ICPCAstana organizers, you did a great job!

From the 12 medalists, 1 came from the Northern Eurasia division, 2 from the North America division, 4 from the Asia East division and 5 from the Asia Pacific division. Is it the best result ever for the Asia Pacific division?.. Sadly, the ETH Zürich team and other teams from our Europe division stopped at 7 problems solved and therefore just shy of the medal boundary.

Problem D in this round required a nice and somewhat unexpected observation. You are given n segments (n<=200000) on the number line. You need to pick one number from each segment, and then pair up some of those numbers in such a way that two numbers in a pair always add up to the given sum s. What is the maximum number of pairs you can form?

One more thing that I did not mention yet about the ICPC World Finals Astana is the CLI symposium. It is a collection of talks by the people that run various aspects of the competitive programming community, for example this year's speakers were Nikolay Kalinin, Riku Kawasaki, Suhyun Park, Antti Laaksonen, Gennady Korotkevich, Andrey Stankevich, Yonghui Wu, Miguel Revilla Rodriguez, Joshua Andersson, Matt Ellis and Christian Yongwhan Lim. You can watch their talks on the ICPC Live channel as well: 1, 2, 3. They are not necessarily at the level of a TED talk, but I think they can provide interesting insights into the thinking of the speakers and into the functioning of the community.

Thanks for reading, and check back next week!