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Leopoldo Taravilse Contest 2025

An informal, highly experimental contest, with the aim of having a lot of fun. Strongly based on MortiContest and on librecontest2020, in the memory of Leopoldo Taravilse

Final Scoreboard

¡Congratulations! We had 18 registered teams. 538 submissions were received in total: 57 submissions from GUEST users, and 481 from registered teams, of which 94 were judged as correct. The Leopoldo Taravilse Contest 2025 was a big success. Thank you everyone and we hope that you had a lot of fun. You can check the problems here, and also submit solutions to be judged by using team secret GUEST.

¡Solutions to all the problems ARE PUBLISHED HERE!

Rules

Duration: 48 hours

Time and date: Starting Friday 9 May 2025 at 20:00 ART (23:00 UTC), and lasting until Sunday 11 May 2025 at 20:00 ART (23:00 UTC)

• For teams between 1 and 3 people, inclusive.
• The contest is created by the contestants themselves: Every team that signs up is strongly encouraged to send a problem statement in pdf format, plus a pdf/txt explaining the corresponding solution [in the end, all of these will be published]. A TEAM THAT SENDS A PROBLEM GAINS TWO POINTS
• In addition to the problems sent by the teams, there will be problems proposed by the organizers.
• It is very important not to share or publish the problems until after the contest has ended. If a team fails to follow this rule, it will be disqualified, and we will all feel very angry :(
• If NO TEAM solves a certain problem (apart from the team that sent it), the team that sent it LOSES 2 points.
• The solution to each problem must NOT be source code, but simply a fixed string between 20 and 1000 characters inclusive. All characters must be ASCII printable characters, with no spaces (ASCII 33 to 126 inclusive). This allows math problems, computing problems, steganography problems, exotic problems... Be creative! Check for example some previous tasks.
• If the solution sent by a team at registration is discovered to be wrong, that team LOSES 10 points.
• 1 point per correctly solved problem. The "first to solve" each problem gets 2 points. For all purposes, a team is considered not to solve its own problem (no points are gained).
• Time penalty and wrong tries do not matter, but at least a minute must pass between consecutive submissions.
• Live Scoreboard

Any language is allowed for problem statements and solutions, but using one of Spanish, English or Portuguese is strongly recommended, unless the point or the idea of the problem is precisely about using an exotic or specific language.

Additional special points

• First, 2/n points are added for having the n-th "strangest" problem (That which maximizes the number of pairs of teams (a,b) such that a finished above b in the scoreboard, but b solved the problem while a did not).
• At the same time (that is, calculations for this step must be made using the original scoreboard before the points from the previous steps are added), 3/n points are added for having the n-th problem when sorting by increasing shared-difficulty. The solving-index of a problem X is r(X): the number of teams that solved it. The shared-difficulty of a problem X is the sum, over all problems Y, of 1/|r(X)-r(Y)|: the reciprocal of the absolute difference between the solving-index of X and Y (or the total number of problems T if r(X)=r(Y)). Intuitively, one must aim for a varied problemset, and particularly, one should try to propose a problem such that its solving-index is far away from that of the other problems: if everybody proposes easy problems, one gets more points by having proposed a hard problem, or if everybody proposes extreme problems (either easy or hard ones), many points are awarded to those who proposed intermediate problems.
• After that, 2/n points are added for having the n-th most voted problem (every team must vote a favourite problem, different from their own problem: a team that does not vote LOSES 10 points in this step).
• Finally, each team has to guess at registration time the percentage (an integer between 0 and 100 inclusive) of the other teams that they will defeat (0% means getting the possibly-tied last place, while 100% means ending strictly above every other team). The team (or teams) that end up closest (having the minimum difference between the forecast and the real percentage, before assigning these points) to their forecast "really get it". That is why, each team gets 2/n points for being the n-th closest team to their forecast.

Registration

Registration deadline: Monday 5 May 2025.

An email must be sent to competencia.leopoldo.taravilse@gmail.com FOLLOWING THIS FORMAT:

Subject: "Competencia Leopoldo Taravilse 2025"

Body:

• A first line with the team's name.
• A second line with the proposed problem's name (write NULL here if the team does not send a problem).
• A third line with a single integer between 0 and 100 inclusive, indicating the forecast percentage of teams that will be defeated by them.
• A fourth line with the number k of team members. 1 ≤ k ≤ 3.
• k additional lines, with the name of one team member per line.

Attachments (only if the team is sending a problem):

• A first attachment "solucion.pdf" or "solucion.txt", containing an explanation of the solution and how to solve the problem, that will be published after the contest ends.
• A second attached file "resultado.txt", having a single line with the expected result.
• A third attached file "enunciado.pdf" or "enunciado.txt", containing the statement that the contestants will download.

Each of these attachments can have a maximum size of 1MB.