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 ...
- 39k
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 ...
- 9,682
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 ...
- 188k
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 ...
- 5,237
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.
...
- 14.8k
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 ...
- 61.7k
16
votes
Somewhere On The Tube ...But On Which Lines?
ES6, Node.js / Chrome, 989 977 931 892 889 887 bytes
...
- 188k
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 ...
- 39k
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 ...
- 26.1k
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$n-k-1]
Terminal nodes are represented by ...
- 7,120
13
votes
13
votes
Do the NP: find the largest clique
Mathematica, 34 bytes
Tr[1^#&@@FindClique[#<->#2&@@@#]]&
Basically FindClique does the job and "finds a largest clique in the graph g."
All ...
- 24.4k
13
votes
Drawing one-liner
Python, 31 bytes
lambda l:sum(n%2for n in l)|2<3
Try it online!
We use k|2<3 to check that ...
- 144k
13
votes
Accepted
12
votes
Accepted
Golf Me An OOP!
CJam, 59 bytes
q_'.e=\N/{)'?=\S/>_,(%}%/(__,*{(2$z~@f=.*\m*|}/ff{1$e=>:=N}
This finishes instantly for both test cases.
It either prints the second name ...
- 210k
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 ...
- 17.5k
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
...
- 166k
12
votes
Knight Distance
Wolfram Language (Mathematica), 64 bytes
Using the built-in KnightTourGraph.
Saved 2 bytes thanks to Mathe172.
...
- 46.5k
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\}...
- 58k
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 ...
- 144k
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 ...
- 32k
11
votes
Only top scored, non community-wiki answers of a minimum length are eligible