48
votes
44
votes
Accepted
Should we be friends?
SWI-Prolog, 62 47 41 bytes
X*Y:-X+Y;Y+X;X==Y.
X?Y:-not(X*Y),X*Z,Y*Z.
Prolog isn't too often useful, but when it is it's just beautiful. We'll use ...
27
votes
Is it a valid chemical?
Python 3, 61 60 59 58 51 bytes
lambda x:len(x)-2<~sum(x)%2*all(x)*sum(x)/2>=max(x)
Try it online!
-1 thanks to @Kevin Cruijssen
-7 thanks to @xnor
Uses ...
23
votes
Get to the Zone!
JavaScript (ES6), 30 bytes
Takes input as (N)(M).
N=>g=M=>M>N?M%2-~g(M+1>>1):N-M
Try it online!
How?
Instead of ...
20
votes
Is it bipartite?
Wolfram Language (Mathematica), 26 25 bytes
Tr[#//.x_:>#.#.Clip@x]<1&
Try it online!
How it works
Given an adjacency matrix A, we find the fixed ...
18
votes
Accepted
Follow incomplete directions
Perl, 150 149 146 145 141 140 138 136 135 133 130 126 125 124
Added +7 for -F -Xn0i
An initial attempt.
Run with the map on STDIN and the directions after the -i option, e.g.
...
17
votes
Can my 4-note music box play that song?
CJam, 34 31 bytes
8,q{~2*f{_@-_zF8b&,@@+8,=*}0-}/
Did this on my phone, so I'll have to put up an explanation later. Output is nonempty iff truthy.
Try it ...
16
votes
Somewhere On The Tube ...But On Which Lines?
ES6, Node.js / Chrome, 989 977 931 892 889 887 bytes
...
16
votes
Accepted
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 ...
15
votes
Hexcellent Minesweeping
7 5 vertices, 14 10 edges
(Graph made with this online tool and paint.)
A-F are our six nodes, and ...
15
votes
14
votes
14
votes
14
votes
13
votes
Enumerate binary trees
Haskell, 68 bytes
t 0=[""]
t 1=["0"]
t n=['(':x++y++")"|k<-[1..n-1],x<-t k,y<-t$n-k-1]
Terminal nodes are represented by ...
13
votes
13
votes
Do the NP: find the largest clique
Mathematica, 34 bytes
Tr[1^#&@@FindClique[#<->#2&@@@#]]&
Basically FindClique does the job and "finds a largest clique in the graph g."
All ...
13
votes
Drawing one-liner
Python, 31 bytes
lambda l:sum(n%2for n in l)|2<3
Try it online!
We use k|2<3 to check that ...
13
votes
Accepted
12
votes
Accepted
Golf Me An OOP!
CJam, 59 bytes
q_'.e=\N/{)'?=\S/>_,(%}%/(__,*{(2$z~@f=.*\m*|}/ff{1$e=>:=N}
This finishes instantly for both test cases.
It either prints the second name ...
12
votes
Accepted
Seeking Leapers
Pyth, 41 35
hfqQu@+G+VM*s_BM*F_BMTGQ]hQ)maVhQdt
Exits on error if there are no valid leapers, giving the empty string if STDERR is ignored.
Try it here or run a ...
12
votes
Should we be friends?
CMD (Batch), 50 + 20 + 135 = 205 bytes
FRIEND.CMD
@for %%f in (%1.%1 %1.%2 %2.%2 %2.%1)do @set %%f=1
KNOW.CMD
...
12
votes
Knight Distance
Wolfram Language (Mathematica), 64 bytes
Using the built-in KnightTourGraph.
Saved 2 bytes thanks to Mathe172.
...
12
votes
12
votes
Who Is Kevin Bacon?
BQN*, 53 45 bytesSBCS
{1+⊑⍒+˝+´(∨∨∨˝∘×⎉1‿∞)⍟n˜∨⟜⍉∨˝𝕩≡⌜1+⋈⌜˜n←↕⌈´∾𝕩}
Run online!
Theory:
Let \$k\$ be the maximum node id. Then the node IDs are \$\{1, 2, ..., k\}...
12
votes
Detect round trips on a dodecahedron
Python 2, 79 bytes
lambda s:all(n==reduce(lambda n,c:-~[n,n%3+n%4][c>'L']%5,s,n)for n in range(5))
Try it online!
This uses the group-theoretic approach from ...
11
votes
Accepted
Loops and Loops and Loops
JavaScript (ES6), 221 229
A function with the input as a parameter, output as a string via popup window (alert).
Scan repeatedly the input:
at each step
remove the end of the tail
count the ...
11
votes
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