Functional Programming Competition 2019

part of the Formal Methods and Functional Programming (FMFP) course at ETH Zürich

Every week a special Haskell programming exercise is published here and in Code Expert. Each exercise is carefully selected by the Master of Competition (MC)—Martin Raszyk—to separate the wheat from the chaff. After 7 weeks, the intersection of the wheat with the FMFP students will receive delicious prizes in a in-lecture ceremony.

Participants submit their solutions via Code Expert. Submissions by mail are accepted only in two exceptional cases: (1) the participant is not enrolled at ETH and therefore cannot use Code Expert, and (2) the solution uses a Haskell library/pragma that is not available on Code Expert. In case (2) precise instructions of how to run the submission (including version numbers) are a necessary requirement for the solution to be evaluated.

Every week, MC's favorite submissions are discussed in a blog post. The submissions are evaluated with respect to different criteria (but the function's correctness is always a must have), which are announced along with the exercise. The best 10 solutions receive from 1 to 10 points (more is better). The points and the names of the participants are made public in a Top 10 of the Week and aggregated in a semester ranking.
Note: Only correct solutions are considered in the ranking. Please write to the MC if you suspect an error in the ranking.

Important: If you don't want your name to appear on a publicly visible webpage (but still want to participate), write to the MC and suggest a pseudonym.

Finally, the MC employs a zero tolerance policy against plagiarism. Please compete fairly and individually. Submissions that have been developed jointly by two contestants have to be clearly marked as such. Violations of those rules may result in arbitrary point deductions.


Top 10 of the Semester
1.Sebastian Haslebacher10681085552
2.Nicolas Emmenegger 🐝087969948
3.Julian Schilliger ♾ 🦊 🤝10100495846
4.Jan Schär 🏆 🦊10356108042
5.Lorenz Holzhauer 🦊 ♟7035910640
6.EnYu Jenp 🏆 🦊0087761038
7.Enrico Bianchi 🏆1016850030
8.Niklas Neugebauer1070057029
9.Flavio Schneider 🏆1016050022
10.Moritz Schneider800840020
10.Christian Ulmann009004720

Full final semester ranking

Task of Week 1

Write a function grade that takes three Int arguments as input — point percentages for the two quizzes and the final exam — and computes the overall percentage1 (rounded down, i.e., a percentage of 99.99% is expressed as 99).

Using an auxiliary function max4 which computes the maximum of four Int arguments, a possible implementation of the function grade looks as follows:
grade q1 q2 e = max4 p1 p2 p3 p4
    p1 = (80 * e + 10 * q1 + 10 * q2) `div` 100
    p2 = (90 * e + 10 * q1) `div` 100
    p3 = (90 * e + 10 * q2) `div` 100
    p4 = (100 * e) `div` 100
    max4 p1 p2 p3 p4 = max p1 $ max p2 $ max p3 p4

For example:

grade 0 0 80 = 80
grade 100 0 80 = 82
grade 0 100 80 = 82
grade 100 100 80 = 84

The shortest (in terms of number of tokens2) solution wins! Library imports and type signatures are excluded from the token count. As a measure of reference: the above solution consists of 78 tokens.

1. Refer to lecture slides for mode details.
2. This competition continues a long-standing tradition of in-lecture functional programming competitions established at TU München and continued at ETH Zürich. The definition of tokens is borrowed form there. Our official token-counting program is available here.

Results of Week 1

Here are the best 10 47 performers in the first competition task.
Top 10 of Week 1
0.MC emeritus19
1.Claudio Abart20
1.Michael Aerni20
1.Enrico Bianchi20
1.Fabian Bosshard20
1.Mauro Bringolf20
1.Damian Cordes20
1.Daniel Frey20
1.Sebastian Haslebacher20
1.Pascal Huber20
1.Loris Reiff20
1.Rasmus Lüscher20
1.Niklas Neugebauer20
1.Luca Näf20
1.Dominic Oertle20
1.Janis Peyer20
1.Simone Riedi20
1.Lukas Ruflair20
1.Carlo Saladin20
1.Julian Schilliger20
1.Flavio Schneider20
1.Luca Schweri20
1.Jan Schär20
1.Remo Senekowitsch20
1.Daniel Sparber20
1.Andras Strausz20
1.Zilin Wang20
2.Alice 24
2.Fiona Muntwyler24
2.Dominic Steiner24
2.Pascal Troxler24
3.Manuel Nowack26
3.Moritz Schneider26
4.Lorenz Holzhauer27
4.Remo Kellenberger27
4.Roberto Starc27
5.Aurel Feer28
5.Peter Jolles28
5.Renato Kunz28
5.Nicolas Marxer28
6.Martin Fiebig29
7.Jonas Hansen30
8.Diluxion Marku31
9.Roman Böhringer32
10.Thore Göbel33
10.Michael Sommer33
10.Viturin Züst33

Full ranking of Week 1

Discussion of Week 1

Task of Week 1 – Follow-Up

Define the function grade or grade' (from Discussion of Week 1) with strictly less than 19 tokens. The first submission (per e-mail to the MC) to improve the current leading t token solution to a t' token solution would get (t - t' + 1)^2 extra points for the semester ranking.

Current leading solutions:

grade = queer `id` replicate 10 .: flip div 10 .:. sum .:. drop 2 .:. on compose1 insert

consisting of 19 tokens,

grade' = flip div 10 .:. sum .:. drop 2 .:. robinstar `id` on compose1 insert `compose1` replicate 10

consisting of 19 tokens.

Task of Week 2

The MC has recently got a list of 1024 integers he would like to sum. Since lists have still not appeared in the lecture, the MC is going to provide his integers as separate arguments to a function sum10.

Your task is to write this function sum10 that takes 1024 Int arguments as input and computes their sum.

The MC has implemented a trivial solution with 112 tokens, but this is too much for the desparate MC! Can you help out?

Remark. If compiling times out on Code Expert, you can test your solution locally using this template. Be patient, compiling may take some time!

Results of Week 2

Here are the best 10 23 performers in the second competition task. All participants who have submitted a (non-trivial) correct solution that does not rely on any extra compiling options have been awarded a trophy for their particularly nice solutions.
Full Ranking of Week 2
0.MC emeritus23
1.Julian Schilliger34
2.Shengyu Huang37
3.Nicolas Emmenegger39
4.Niklas Neugebauer40
4.Janis Peyer40
5.Sebastian Haslebacher41
5.Michael Sommer41
6.Andrin Bertschi46
6.Nicolas Wicki46
7.Loris Reiff49
8.Carlo Saladin 🏆57
8.Jan Schär 🏆57
9.Gabriel Giamarchi 🏆60
10.Enrico Bianchi 🏆61
10.Simone Riedi 🏆61
10.Flavio Schneider 🏆61
11.Daniel Sparber75
12.Moritz Schneider81
13.Nicolas Hoferer 🏆114
14.EnYu Jenp 🏆152
15.Rasmus Lüscher3073
15.Mathias Vetsch3073

Discussion of Week 2

Task of Week 2 – Follow-Up

Define the function sum without relying on any extra compiling options (module imports are still allowed and do not contribute to the token count). The first submission (per e-mail to the MC) to improve the current leading t token solution to a t' token solution would get (t - t') extra points for the semester ranking.

Current leading solution:

module Sum where

import Data.Aviary.Birds
import Data.Composition

--sum10 :: Int -> Int -> Int -> [...] (omitted here for clarity)
sum10 = comb9 $ comb9 id 0

comb1 f = f .:. jay (+)

comb3 = comb1 . becard comb1 comb1 comb1
comb5 = comb3 . becard comb3 comb3 comb3
comb7 = comb5 . becard comb5 comb5 comb5
comb9 = comb7 . becard comb7 comb7 comb7

consisting of 48 tokens.

Task of Week 3

Announcement: the MC has decided to extend the deadline for Week 3 until Saturday, March 16th, 24:00. The MC wishes you much success at the QUIZ!

The MC has recently found a module STR, but has no clue about its purpose. He is particularly curious about the function cnt. But its running time grows so rapidly that the MC is not able to evaluate it on lists of length more than 5.

Could you help the MC by providing an efficient implementation of the module STR such that the function cnt from your implementation is equal to its counterpart in the original module?

Your solution will be ranked based on the length of lists it can evaluate within a fixed timeout. In more detail, your solution will be run on a group of lists of the same length and will pass the group if the total running time to evaluate all lists from the group does not exceed the timeout. Solutions that do not implement the exact behaviour of the original module will NOT be considered.

As a measure of reference, the MC would like to be able to evaluate the funcion cnt on a list of length 250 within a few seconds.

Note. You may assume that all values in the input list fit into the range of Int. Nevertheless, the type of the function cnt must still be cnt :: [(Integer, Integer)] -> Integer.

module STR where
import Data.List

elem' = \x xs -> elem x xs || elem (swap x) xs
swap (x, y) = (y, x)

combine [] ys = []
combine (x:xs) ys = (map ((,) x) ys) ++ (combine xs ys)

remeq = filter (\(v1, v2) -> v1 /= v2)

prep _ [] = []
prep f (x:xs) = aux x $ prep f xs
    aux x xs
      | f x xs = xs
      | otherwise = x:xs

check vs es = (length es == length vs - 1) && (not $ elem False (map (\p -> elem (Just p) paths) pairs))
    pairs = remeq $ combine vs vs
    paths = map compress $ filter checkPath $ concatMap permutations $ subsequences $ concatMap maybeRev es
    maybeRev p = [p, swap p]
    checkPath es = snd $ foldr checkConsecutive (Nothing, True) es
    checkConsecutive (v1, v2) (Nothing, b) = (Just v1, b)
    checkConsecutive (v1, v2) (Just v, b) = (Just v1, b && (v2 == v))
    compress [] = Nothing
    compress ((v1, v2):vs) =
      let res = compress vs in
      case res of
        Nothing -> Just (v1, v2)
        Just (v1', v2') -> Just (v1, v2')

post [] = 0
post (x:xs) = 1 + post xs

cnt :: [(Integer, Integer)] -> Integer
cnt es = (post . filter (check vs) . subsequences . remeq . prep elem') es
    vs = prep elem $ concatMap (\(x, y) -> [x, y]) es

You can also find the module here.

Results of Week 3

Here are the best 10 11 performers in the third competition task. The MC received six more solutions before the extended deadline. Three of them were wrong and could not be further considered. Julian Schilliger — the leader of the ranking after Week 2 — had been on the second place in the preliminary ranking, but has introduced an infinite loop in his final solution and could not be included in the final ranking. He deserves the infinity emoji ♾ in the semester ranking. On the positive side, Nicolas Emmenegger has improved his solution during the deadline extension. He deserves the hard worker emoji 🐝 in the semester ranking.

Preliminary Ranking of Week 3
#namemax length
1.Ke Yi Tan1540
2.Julian Schilliger224
3.Sebastian Haslebacher196
4.Enrico Bianchi65
4.Flavio Schneider65
4.Nicolas Emmenegger65
5.Fabian Bosshard32
6.Lorenz Holzhauer22
7.Lukas Schmid5
Full Ranking of Week 3
#namemax length
1.Ke Yi Tan1540
2.Christian Ulmann241
3.EnYu Jenp196
3.Sebastian Haslebacher196
4.Nicolas Emmenegger 🐝166
5.Enrico Bianchi65
5.Flavio Schneider65
6.Jan Schär37
7.Fabian Bosshard32
8.Lorenz Holzhauer22
9.Lukas Schmid5

Discussion of Week 3

Task of Week 4

After the reverse engineering task from last week, let's do some stringology this week. It is a standard problem to check if a string is a substring of another string (i.e., to search a needle in a haystack). For example, the string "FM" is a substring of the string "FMFP", but the string "FF" is not a substring of the string "FMFP". Moreover, a string is a substring of itself and the empty string is a substring of any string.

Let's generalize the problem as follows: given a string h and a list of strings ns, count for each string n from the list ns how many times n occurs in h as a substring. We also count overlapping occurrences of a substring, i.e., the string "ABA" occurs twice in the string "ABABA" as a substring.

Your task is to write a function countRepeats :: String -> [String] -> [Int] that solves the generalized problem as fast as possible. You may assume that the symbol '$' (dollar sign) appears in neither the haystack nor any needle.

For example:

countRepeats "FMFP" ["FM", "FF"] = [1,0]
countRepeats "ABABA" ["ABA", "A", "C", ""] = [2,3,0,6]

The function countRepeats can be implemented as follows:

module Stringology where

import Data.List

countRepeats :: String -> [String] -> [Int]
countRepeats h ns = map (\n -> length $ filter (isPrefixOf n) $ tails h) ns

but the time complexity of this implementation is not particularly impressive. Nevertheless, you can download the sample implementation here.

Your solution will be evaluated on inputs satisfying (sum $ map length ns) ≤ (length h), i.e., the sum of lengths of all needles in ns does not exceed the length of the haystack h. Let |h| = length h denote the length of the haystack. Your solution will be ranked based on the maximum |h| of inputs it can evaluate within a fixed timeout. In more detail, your solution will be run on a group of inputs with the same |h| and will pass the group if the total running time to evaluate all inputs from the group does not exceed the timeout. Solutions that do not implement the exact behaviour of the sample implementation will NOT be considered.

As a measure of reference, the MC has a three-line solution that can evaluate any input satisfying |h| = 100 000 within a few seconds.

Results of Week 4

Here are the best 10 10 (indeed!) performers in the fourth competition task. The four participants sharing the bronze medal just handed in the provided sample solution! On the other hand, the last four participants tried to optimize it by using the KMP algorithm or some smart refactoring. They deserve the Schlaufuchs emoji 🦊 in the semester ranking. Cordial CONGRATULATIONS go to the leader of the ranking — Sebastian Haslebacher — who realized that the Aho-Corasick algorithm fits better than the KMP algorithm for this week's task.

Full Ranking of Week 4
#namemax length
1.Sebastian Haslebacher313000
2.Nicolas Emmenegger49000
3.Enrico Bianchi42000
3.Gabriel Fringeli42000
3.Rasmus Lüscher42000
3.Moritz Schneider42000
4.EnYu Jenp 🦊29000
5.Jan Schär 🦊17000
6.Lorenz Holzhauer 🦊15000
7.Julian Schilliger 🦊9000

Discussion of Week 4

Task of Week 4 – Follow-Up

WARNING! Solutions found on the web will not be awarded any points for the semester ranking, but the MC would like to hear about them and will award the fairplay emoji 🤝 for them.

Write the function countRepeats :: String -> [String] -> [Int] implementing the Aho-Corasick algorithm and taking |h| steps, where |h| is the length of the haystack. The assumptions from Week 4 apply here. Instructions on how to extend the Aho-Corasick algorithm to achieve this time complexity can be found in the Discussion of Week 4.

The first correct solution received by the MC by mail will be awarded 4 extra points for the semester ranking.

Current status: UNSOLVED.

Write a function construct :: String -> MCSTree Char building a suffix tree in linear time. The goal is to have an efficient construction of the suffix tree which can be plugged in MC's solution from the Discussion of Week 4. A possible implementation that runs in super-linear time is commented out below.

module Stringology where

type MCEdge a = ([a], MCSTree a)
data MCSTree a = MCNode [MCEdge a] Int | MCLeaf

countMCSTree :: MCSTree Char -> Int
countMCSTree MCLeaf = 1
countMCSTree (MCNode _ c) = c

countNeedle :: String -> MCSTree Char -> Int
countNeedle [] t = countMCSTree t
countNeedle n (MCNode es _) = go es
    go [] = 0
    go (e:es') = aux es' (snd e) (suffix n $ fst e)
    aux es' _ Nothing = go es'
    aux _ t (Just n') = countNeedle n' t
    suffix (x:xs) (p:ps)
      | x == p = suffix xs ps
      | otherwise = Nothing
    suffix xs _ = Just xs

countRepeats :: String -> [String] -> [Int]
countRepeats h ns = map (\n -> countNeedle n tree) ns
    l = length h
    tree = construct h

construct :: String -> MCSTree Char
construct = undefined
construct h = foldTree $ SuffixTree.construct (h ++ "$")
    foldTree SuffixTree.Leaf = MCLeaf
    foldTree (SuffixTree.Node es) = MCNode (zip ps es') (sum $ map countMCSTree es')
        es' = map (foldTree . snd) es
        ps = map (SuffixTree.prefix . fst) es

The template can also be downloaded here.

The first correct solution received by the MC by mail will be awarded 4 extra points for the semester ranking.

Current status: UNSOLVED.

Task of Week 5

You might have played the game Regex Golf whose objective is to produce a short regular expression (regex) matching all strings from a given list and, at the same time, matching no string from another given list. This week, we make your life easier (or harder?) by relaxing the rules of the game as follows: you are given a single list of strings and you need to come up with a short regex matching at least one string and also not matching at least one string from the list. A straightforward solution is to compute a regex matching exactly the first word from the list and nothing else. But there might be better solutions in terms of size of the final regex.

Your task is to write a function minregex :: [String] -> RE that takes a list of strings as input and computes a short regex matching at least one string and also not matching at least one string from the list. The data type for a regex looks as follows:

data RE = Zero          -- Zero matches nothing
        | One           -- One matches only the word []
        | Dot           -- Dot matches any single letter word,
                        -- e.g., ['a'] or ['b'], but neither [] nor ['a', 'b']
        | Atom Char     -- Atom c matches only the word [c]
        | Plus RE RE    -- Plus r s matches all words matched by r or s
        | Concat RE RE  -- Concat r s matches all words w = u ++ v
                        -- such that u is matched by r and v is matched by s
        | Star RE       -- Star r matches [] and all words w = u ++ v
                        -- such that u is matched by r and v by Star r

WARNING! You are not allowed to change this data type! You may download the module for regular expressions with a sample implementation here.

Announcement: The sample module has changed slightly — now the part of the module you may not modify excludes the first line of the module declaration so that you can import other modules if you wish.

Announcement: The way in which your solution will be evaluated has slightly changed — please make sure to check out the next paragraph again.

In addition to the function minregex, you have to create a list of test cases tests :: [[String]] that will be used to evaluate your solution as follows. Suppose there are N submissions to this week's assignment. Each of these N submissions will be run on your tests and your final score will be equal to twice the median sum of sizes of your competitor's regular expressions for your tests minus twice the sum of sizes of your regular expressions for your tests (note that if N is even, then the median is the mean of the two middle values). Note that your final score might also be negative. Clearly, a higher score is better. Also note that your final score depends on the quality of both your function minregex and your test cases tests.

If the function minregex fails with an exception or does not complete within a fixed timeout (corresponding roughly to evaluating head $ drop 500000000 [1..]), the default implementation will be used on that particular test case. Each string must consist only of lower-case letters from the English alphabet. Test cases with less than two different strings will be ignored. Moreover, the total length of all strings must not exceed 1000, i.e., length (concatMap concat tests) ≤ 1000 must hold.

Results of Week 5

Here are the best 10 13 performers in the fifth competition task. Finally, we could observe an increase in the number of submissions (jay!). To prevent potential unfair collaboration, the MC changed the evaluation (see an announcement above). Recall that before the change, the final score was supposed to equal the sum of sizes of your competitor's regular expressions for your tests minus (N - 1)-times the sum of sizes of your regular expressions for your tests (where N is the total number of submissions). However, the MC could not resist the temptation to evaluate the round in both ways. Clearly, only the official one will be considered for the semester ranking.

Unofficial Ranking of Week 5
1.Jan Schär10893
2.Julian Schilliger9910
3.Lorenz Holzhauer8597
4.Sebastian Haslebacher6549
5.Enrico Bianchi5994
6.Nicolas Emmenegger2653
7.EnYu Jenp2493
8.Soel Micheletti4
8.Niklas Neugebauer4
8.Simone Riedi4
8.Flavio Schneider4
9.Moritz Schneider-65
10.Fabian Bosshard-1968
Official Ranking of Week 5
1.Jan Schär1978
2.Lorenz Holzhauer1972
2.Julian Schilliger1972
3.Sebastian Haslebacher1508
4.EnYu Jenp994
5.Nicolas Emmenegger618
6.Enrico Bianchi0
6.Fabian Bosshard0
6.Soel Micheletti0
6.Niklas Neugebauer0
6.Simone Riedi0
6.Flavio Schneider0
7.Moritz Schneider-15

Discussion of Week 5

Task of Week 6

Announcement: The deadline for this challenge has been extended to Tuesday, 2nd April, 23:59 CEST.

Announcement: Timing the players and ASCII art output has changed in the module Quoridor to be more reliable. Please check out the updated module (uploaded on 31st March, 11.22 CEST).

Announcement: The winner of this round will receive a special prize!

This task is rather different from the ones before: implement a strategy for playing Quoridor. There is no Code Expert project this time. Instead, please submit your solutions by mail to the MC.

Note that there are only two pieces on the board in our game.

Quoridor is a strategy game played on a 9 × 9 board with two pieces and twenty fences distributed equally between the two players. Initially, the two pieces are centered at opposite sides of the board and the goal of the game is to reach the opponent's side of the board. In each move, a player may move its piece to an adjacent field or place one of its remaining fences on the board (either horizontally or vertically). A fence always separates two pairs of fields. Once placed, a fence may not be moved or removed. It also prevents any piece from jumping over it. Nevertheless, the fences must be placed in a way that guarantees both players a path from their field to the respective side of the board they need to reach (maybe via a detour). Please check out the Wikipedia article for the full rules of the game. The MC also encourages you to try out the game before implementing your strategy. To win, you must be the first player to move your piece on the opposite side of the board using only legal moves and at most 5 minutes spent evaluating your step function (deciding on your moves).

The MC has prepared a module Quoridor defining data types for the state of the game, a player's move, and a player's strategy. It also contains functions for checking if a move is legal and a function simulating supplied two players' strategies. The MC further provides a sample module PlayerRANDOM implementing a simple strategy for the two players. Finally, the MC provides a tournament module Main illustrating how this week's task will be evaluated. You might need to install a few Hackage packages to load the modules. The instructions are in the sources.

The state (State) of the game consists of the two player's positions (Pos = (Int,Int)), the numbers of the two player's remaining fences, and arrays storing the positions of the fences on the board. The fields on the board are indexed by positions between (1,1) and (9,9), where (1,1) is the bottom left corner of the board. For the sake of implementation, the winning fields of the first player (above the board's topmost row) are indexed by position between (1,10) and (9,10). The first player may reach those fields by jumping over the opponent's piece at the topmost row. Analogously, the winning fields of the second player (below the board's bottommost row) are indexed by position between (1,0) and (9,0). The array hFence stores for each field with position (x,y) between (1,0) and (9,9) whether there is a horizontal fence directly above it, i.e., separating the field (x,y) from the neighbouring field (x,y+1). Analogously, the array vFence stores for each field with position (x,y) between (1,0) and (8,10) whether there is a vertical fence directly to the right of it, i.e., separating the field (x,y) from the neighbouring field (x+1,y). Finally, the array cross stores for each field with position between (1,1) and (8,8) whether the junction at its top right corner is empty or taken by a fence.

A move (Move) of a player has one of the following three forms (1) Piece Bool Pos, where the Bool must be set to True iff it is a move of the first player and the Pos denotes the field where the player wants to move its piece on; (2) HFence Bool Pos, where Pos is a position (x,y) between (1,1) and (8,8) such that the respective player (according to the Bool) wants to place a horizontal fence directly above the fields (x,y) and (x+1,y); (3) VFence Bool Pos, where Pos is a position (x,y) between (1,1) and (8,8) such that the respective player (according to the Bool) wants to place a vertical fence directly to the right of the fields (x,y) and (x,y+1).

A player's strategy for Quoridor is a pure function of type step: Double -> State -> m -> (m, Move) that inputs the remaining time (in seconds), a state, and some polymorphic memory slot, which you may instantiate with any type you want and use it to store reusable information. The function should return the next move (Move) together with an update of the memory. Be careful to produce only legal moves (producing illegal ones is an additional losing condition).

A player (Player) is then characterized by such a function extended with a name (please use your nethz in UPPER-CASE) and an initial memory content. Note that evaluating the initial memory contributes to your time limit of 5 minutes.

Please submit a single file called PlayerNETHZ.hs which implements two Players: player1 that starts at the bottommost row (and has the first move) and player2 that starts at the topmost row (and goes second). In particular, you are not allowed to modify the content of the modules Quoridor nor Main, but may implement your own optimized functions in the module PlayerNETHZ that have the same functionality as some of the functions from Quoridor.

The submissions will be evaluated in a tournament. For each pair of submissions, the Main module will be instantiated with the provided strategies (in both ways) and the winner scores one point. In particular, if there are N submissions this week, then N * (N - 1) points will be distributed in total. The ranking will then be based on the total number of points your two player strategies have scored.

Graphical visualizations of the game that are nicer than the ASCII art of the MC are very welcome contributions, too. The MC is not sure, if they would yield any competition points, though (this depends on their beauty).

Results of Week 6

Here are the best 10 8 performers in the game week. The winner — Lorenz Holzhauer — deserves the game emoji ♟ and a special prize awarded in the last lecture.

Full Ranking of Week 6
#nametotal score
1.Lorenz Holzhauer ♟13
2.Nicolas Emmenegger11
3.Jan Schär8
4.Niklas Neugebauer7
5.EnYu Jenp6
6.Sebastian Haslebacher5
6.Julian Schilliger5
7.Christian Ulmann1

Discussion of Week 6

Task of Week 7

This task is the final task of the competition. The submission deadline is on Tuesday, 2nd April, 23:59 CEST. The results (of this task and the entire competition) will be announced (and followed by the award ceremony) in the last lecture of the FP part of the course on Thursday, 4th April. The last year's slides can be found here.

The actual task is very simple: Be original!

You are required to submit by mail to the MC a picture with any content you want (in one of the following formats: jpg, png, svg, pdf, gif) and a Haskell program (a single file: Art.hs) that was used to generate the picture. Here are some examples of graphics libraries that you are encouraged to use (others are welcome, too).

The pictures will be evaluated with respect to the aesthetics of the artwork (by an independent but highly subjective jury) and the aesthetics of the code (by the independent but highly subjective MC).

Hint: Such an artistic task is a traditional ending of a competition. You can look at previous year's submissions for some inspiration. Various fractals have been fairly popular among the past submissions. If done properly (i.e., beautifully), they will guarantee you a secure place somewhere in the middle. But typically, to win this task one has to create something more original and surprising.

Results of Week 7

Here are the best 10 6 performers in the art gallery week. The jury comprised 7 members who ranked the submitted pieces of art relatively to each other (possibly with ties) and the MC then mapped the rankings to points as usual (10 is the best) and summed them together.

Full Ranking of Week 7
#nametotal score
1.EnYu Jenp64
2.Nicolas Emmenegger63
3.Julian Schilliger56
4.Christian Ulmann52
5.Lorenz Holzhauer45
6.Sebastian Haslebacher43

Art gallery