TUM NWERC Selection Process 2020

As every year it is about time to decide who is going to represent TUM in the 2020 ICPC Northwestern Europe Regional Contest (NWERC). Due to the COVID-19-pandemic it is not clear at this point in which format (onsite in Iceland or remote) the NWERC 2020 is going to take place. Nevertheless, we would like to proceed with our usual selection process so that we are prepared for any scenario. Similar to previous years, we assume that TUM will be granted between 2 and 4 (most likely 3) spots in the NWERC 2020. As each team consists of up to 3 students, there will be in total 6 to 12 students able to qualify for the NWERC. After careful deliberation, we came up with quite an involved selection procedure last year that enjoyed a high popularity among our students. We therefore decided to conduct a similar selection procedure this year. It is based on student's performance in a number of upcoming online contests. Please read the details below and contact us in case you have any questions or would like to enter the selection process.

Eligibility

Everyone who is (or will be) enrolled as a TUM student in the winter semester 2020/2021 and is eligible to participate in the NWERC 2020 according to the official 2020 ICPC Regionals Eligibility Decision Diagram is welcome to participate in our TUM NWERC selection process.

For more information regarding the eligibility rules for the 2020 ICPC Regional contests, please click here.

Selection Period

27.07.2020 - 20.11.2020

Ranked Contest

• Atcoder Grand Contests
• Codeforces Educational Contests
• Codeforces Global Contests
• Codeforces combined Div1 & Div2 Contests and exclusive Div1 Contests (both types are rare, though)
• Additional suitable contests may be included by the TUM organization team (a.k.a. ’the Gregors’) once they are announced

Scoring Function

For each ranked contest, every student gets assigned a score measuring his/her performance in the contest. The score takes into account how many tasks a student solved and how difficult those tasks were. It is calculated as follows:

• Every task gets assigned a number of points after the contest. For task i this is p_i = (1 - log(percentage of solutions for the task among all contestants in the contest)) (natural logarithm) For example if there are 10 000 contestants and m contestants solve a task, this task gives: m = 10 000: 1, m = 8000: 1.22, m = 5000: 1.69, m = 2500: 2.39, m = 1000: 3.3, m = 500: 4, m = 250: 4.69, m = 100: 5.61, m = 50: 6.3, m = 25: 6.99, m = 10: 7.91, m = 5: 8.6, m = 2: 9.52, m = 1: 10.21 points.
• Then, a preliminary score is calculated for every contestant. For contestant j, this is c_j = sum over each task i of (1 if solved and 0 otherwise) * p_i
• Finally, the score of every contestant is computed as s_j = c_j / (average preliminary score among all contestants in the contest) “All contestants” refers to the number of people that uploaded at least one submission.

For the selection process, every participant is then assigned a total score based on his/her performances in the contests during the selection period. This total score t_j is the sum of the scores s_j of this participant in the individual contests, but only taking the best 4 contests of the participant into account.

Forming Teams

The best 9 participants according to their total score in the selection process create teams through a public discussion. If no consensus can be achieved, we use the following strategy: Students are ranked according to their individual scores. Ties are broken uniformly at random. The student with the best rank may now start to select his/her teammates. The student can ask any student who participated in the selection process to be his/her teammate. The student’s potential teammate can accept or reject this request. Once a team is formed, the student with the highest individual score but unassigned to a team may choose his/her teammates, and so on.

Telegram Group & Selection Bot

Some of our students wrote a great Telegram bot that automatically fetches the contest data from various platforms, calculates the new scores, and pushes these scores into our ICPC TUM Telegram group.

How to join the qualification

In case you want to take part in the selection process, please send us a message to icpc(at)in.tum.de including your full name, your codeforces and atcoder handles, and whether or not you're already in our ICPC TUM Telegram group.

Contact

Gregor Matl & Gregor Schwarz
icpc(at)in.tum.de

(This article has been updated after the selection period has been extended.)