Santa’s Algorithmic Challenge

Ho ho ho! Every year, Santa passes by EPFL before Christmas, to judge nice students based on their algorithmic performance.

The Challenge is organized by Prof. Kapralov, in collaboration with PolyProg and Yandex.
It is focused on Bachelor students, specifically those in second year taking the “Algorithms” class, but open to all EPFL students.

Yandex logo Santa’s Algorithmic Challenge is sponsored by Yandex.


The 2017 edition happened on Monday, November 27.

When What Where
16:15 Welcome! BC Atrium
16:30 Introduction to the contest BC Atrium
16:45 Time to try out everything INF 3 / BC 07-08
17:00 The contest! INF 3 / BC 07-08
20:00 Food and drinks BC Atrium
20:30 Prize ceremony BC Atrium
21:00 More food, open end… BC Atrium


Your goal in the challenge is to solve as many tasks as possible, while having fun.

You are eligible to participate only if you are a student at EPFL, including exchange students and PhDs.
Bachelor students may be prioritized if there are too many registrations.

Programming tasks will be there for you to solve.
Each of them requires you to find the right algorithm and implement it in a short program.

1 point is what you get for each completely solved task.
A task is completely solved when your program produces the right output for all test cases, within the time limit.

Time and wrong submissions are used to rank teams that solved the same number of tasks.
Total time is a tie-breaker, where less is better; it is the sum of all intervals from the contest beginning to a correct submission.
Each incorrect submission gives you a 20 minute penalty.

3 hours is the duration of the contest.

1 PC per team is allowed.

Cheating is when you try to communicate with other teams, access unauthorized websites, or mess with the contest.
You shouldn’t do this. Otherwise, Santa might put you in his bag and take you with him.


During the challenge, your team will use one computer to write programs, and submit those to

You will use a computer running our custom environment, with the following software:

Reference documentation for all supported languages will be available during the contest, at

Internet access is prohibited outside of the juding contest and documentation.