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54 votes

Absolute Sums of Sidi Polynomial Coefficients

Python 2, 43 bytes f=lambda n,k=1:k/n or n*f(n,k+1)+k*f(n-1,k) Try it online! A different approach Ever since I posted this challenge, I tried to come up with a ...
Dennis's user avatar
  • 210k
31 votes

Anaglot Polygrams

34 Languages, 19 bytes, Score: 38,832,018,459,912,437,760,000 Here is a quick answer I threw together to show that it is possible to get an answer scoring better than 1. ...
Wheat Wizard's user avatar
  • 98.9k
29 votes

Every word from babab to zyzyz

Mathematica, 72 65 61 bytes Print@@@Tuples@{a=##/(b=#5#9#15#21#25#)&@@Alphabet[],b,a,b,a} For testing, I recommend replacing ...
Martin Ender's user avatar
26 votes

Concentric rings on a snub square tiling

Ruby, 26 bytes ->n{~-n*12-496/4**n%4+1/n} Try it online! Revised version adding 1/n and subtracting ...
Level River St's user avatar
25 votes

The square root of the square root of the square root of the…

APL (Dyalog Unicode), 39 bytes +/⊢{∨/⍺⍵<⍵0:0⋄⍺=0:1⋄+/∊∇¨/⍺(⍵*2)-⊂⍳⍺}¨⍳ Try it online! A tacit function containing an inner dfn to use recursion. Does not use ...
Bubbler's user avatar
  • 77.2k
24 votes

Sticky polyhexes

Haskell, 320…236 230 bytes ...
Delfad0r's user avatar
  • 6,276
24 votes

Counting universal n-ary logic gates

Python 3.8 (pre-release), 287 282 242 bytes -5 bytes thanks to @Dialfrost ...
AnttiP's user avatar
  • 7,898
23 votes

Brute-force the switchboard

Haskell, 25 24 23 17 bytes mapM$min"^v".pure Try it online! -1 byte thanks to @H.PWiz -1 byte thanks to @nimi Returns a list of strings. The TIO has 2 extra ...
cole's user avatar
  • 4,006
21 votes

Don't repeat yourself in Rock-Paper-Scissors

Ruby, 39 bytes ->n{(?P*n..?S*n).grep_v /[^RPS]|(.+)\1/} This hilariously inefficient function generates all strings of length N that lie alphabetically ...
histocrat's user avatar
  • 22.2k
20 votes

Deranged !Combinatorics: Compute the Subfactorial

Funciton, 336 bytes Byte count assumes UTF-16 encoding with BOM. ...
Martin Ender's user avatar
20 votes

Partitioning the grid into triangles

Haskell, 60 55 54 52 bytes After a drawing and programming a lot of examples, it occured to me that this is the same as the problem of the rooks: On a \$(n+1) \times (n+1)\$ chessboard, how many ...
flawr's user avatar
  • 43.8k
18 votes

A penny saved is a penny

Haskell, 37 34 bytes s#l@(c:d)|s>=c=(s-c)#l+s#d s#_=0^s Usage example: 26 # [1,5,10,25] -> ...
nimi's user avatar
  • 35.9k
18 votes

Converge to a number

Jelly, 9 bytes DLḶU⁵*xDÄ Try it online! ...
lynn's user avatar
  • 68.8k
18 votes

Enumerate all pure sets

Python, 43 bytes f=lambda x:[f(i)for i in range(x)if x>>i&1] Attempt This Online! Outputs the \$ n \$th set, starting at \$ 0 \$. One way of creating a sequence of all pure sets is to encode ...
pxeger's user avatar
  • 23.9k
17 votes

Generate all combinations of given list of elements, sorted

Jelly, 1 byte TryItOnline Cartesian power built-in atom, as a dyadic link with left argument the items and right argument the count, or as a full program with ...
Jonathan Allan's user avatar
16 votes

Super permutations

Scratch 3.0, 65 blocks / 637 632 bytes Look at y'all, having fun with your fancy shmancy permutation functions/map tools. Well, not I! No, not I! When using Scratch, one has to do things themselves! ...
lyxal's user avatar
  • 33.7k
16 votes

Never trust a mastermind

JavaScript (ES6),  116 112  107 bytes Expects an array of entries in the following format: [[a,b,c,d], "XY"], where a ...
Arnauld's user avatar
  • 194k
16 votes

Cut a triangle into equal-sized parts!

JavaScript (ES7),  367 362 359  357 bytes Saved 1 byte thanks to @Shaggy Expects (n)(m). ...
Arnauld's user avatar
  • 194k
16 votes

Just Enough Ones

J, 41 bytes 1#.*:=1#.2>[:>@~.@,[:+&,&.>/~i.@!<@A.=@i. Try it online! A different take on brute force, which handles up to n=6 on TIO. Since the ...
Jonah's user avatar
  • 33.6k
15 votes

A penny saved is a penny

Mathematica, 35 22 bytes Thanks to miles for suggesting FrobeniusSolve and saving 13 bytes. Length@*FrobeniusSolve Evaluates ...
Martin Ender's user avatar
15 votes

Arranging Bubbles

Python 2, 92 87 bytes a=lambda n:n<2or sum((k%d<1)*d*a(d)*a(n-k)for k in range(1,n)for d in range(1,1+k))/~-n In plain english: to compute ...
orlp's user avatar
  • 39.1k
15 votes

Largest monetary amount impossible to make with two types of coin

J, 7,6 3 bytes -1 byte thanks to FrownyFrog ! -3 bytes thanks to Grimmy! *-+ Try it online! ...
Galen Ivanov's user avatar
14 votes

Every word from babab to zyzyz

Perl, 47 bytes #!perl -l /((^|[aeiouy])[^aeiouy]){3}/&&print for a..1x5 Counting the shebang as one. Try it online!
primo's user avatar
  • 33.3k
14 votes

Permutations in Disguise

Python 2, 60 bytes def f(l):z=zip(l,range(len(l)));print map(sorted(z).index,z) Try it online! Uses zero-indexing. A fast algorithm with a simple idea. If we ...
xnor's user avatar
  • 145k
14 votes

Number of distinct tilings of an n X n square with free n-polyominoes

C, 7 terms The seventh term is 19846102. (The first six are 1, 1, 2, 22, 515, 56734, as stated in the question). ...
Grimmy's user avatar
  • 15.8k
14 votes

Triangular domino tiling of an almost regular hexagon

APL (Dyalog Classic), 14 bytes ×/1+1÷1+∘,1⊥¨⍳ Try it online! Uses 0 indexing with ⎕IO←0. Explanation: ...
Jo King's user avatar
  • 47.3k
14 votes

Stack Exchange Answerer

Python 3.8, 81, 79, 75 bytes Using the walrus operator :=: ...
game0ver's user avatar
  • 671
14 votes

(RGS 2/5) How many strings can you count within these character classes?

CP-1610 machine code (Intellivision),  23  22 DECLEs1 ≈ 28 bytes As per the exception described in this meta answer, the exact score is 27.5 bytes (220 bits) A routine taking a null-...
Arnauld's user avatar
  • 194k
14 votes

Rectangles in rectangles

Python 2, 66 59 bytes lambda n,k:sum(a%n*(n-a%n)==a/n*(k-a/n)for a in range(n*k)) Try it online! Each possible rectangle inside the \$n \times k\$-rectangle can ...
ovs's user avatar
  • 59.7k

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