LibreContest 2020

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

Final Scoreboard

Congratulations! With 5 officially competing teams, and 103 submissions received, the first edition of librecontest has been a success. Thank you everybody, we really hope you had fun. Problems can be read here, and it is also possible to submit solutions using team secret GUEST (although no proof will be manually checked).

You can check solutions for every problem.

Posición / Rank	Team	Problem 1	Problem 2	Problem 3	Problem 4	Problem 5	Problem 6	Problem 7	Problem 8	Problem 9	Problem 10	Problem 11	Total	Rarity	Missing Dif.	Most voted	Really get it	Final score
1	The Fantastic Crocodiles (Quimey Vivas + Federico Felguer)	1	2	0	1	1	0	2	2	2	1	2	14	2	1	1	1	19
2	GG Dem (Sebastián Marin + Marcos Kolodny + Mateo Carranza Vélez)	0	1	0	2	1	2	1	1	1	2	1	12	1	0.6	0.5	0.66	14.766
3	MNaeraxr (Marcelo [marX])	2	0	0	0	1	0	1	1	1	1	1	8	0.5	0.6	0.5	0.5	10.1
4	Guty (Facundo)	0	0	2	0	1	0	0	0	0	1	0	4	0.5	0.375	0.5	2	7.375
5	DijkstraEnConstante (Juan Ignacio Cantarella + Gastón Fontenla Núñez + David Lescano)	0	0	0	0	2	0	0	0	0	1	0	3	0.5	0.375	0.5	0.4	4.775

Rules

Duration: 48 hours

Time and date: Starting Friday 13 March 2020 at 20:00 ART (23:00 UTC), and lasting until Sunday 15 March 2020 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 MUST send a problem statement in pdf format. Also, each team must send a pdf/txt explaining the corresponding solution [in the end, all of these will be published].
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 3 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!
If the solution sent by a team at registration is discovered to be wrong, that team LOSES 20 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 ranking by missing-difficulty. The solving-index of a problem is the percentage of teams that solved it. The missing-difficulty of a problem X is the sum, over all problems, of the square of the difference between the solving-index of X and that of the other problem. 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.

Inscription

Inscription deadline: Thursday 12 of March.

An email must be sent to librecontest2020@gmail.com FOLLOWING THIS FORMAT:

Subject: "LibreContest 2020"

Body:

A first line with the team's name.
A second line with the problem's name.
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:

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.