Arrow those variables!

Question

Challenge

Robin likes having his variables declaration in the shape of an arrow. Here's how he does it:

• Input any number of strings
• Order them by ascending length

• Output them ordered by the middle to roughly form a negative arrowhead, like this (whichever order golfs the best):

  5  or  4
  3      2
  1      1
  2      3
  4      5
  

Test Cases

Input:

bow
arrows
sheriffOfNottingham
kingRichard
maidMarian
princeJohn
sherwoodForest

Output:

sheriffOfNottingham
kingRichard
maidMarian
bow
arrows
princeJohn
sherwoodForest

Input:

a
bb
cc

Output (both are valid):

bb
a
cc

cc
a
bb

Input:

one
four
seven
fifteen

Possible output (the only other valid output is its vertical mirror):

seven
one
four
fifteen

Notes

• The strings are in camelCase and have no numbers or special characters, only lowercase and uppercase letters.

• The input can be anything you like: comma-separated as one string, array, ... Any I/O format is allowed.

• Between strings with the same length, any order is accepted.

Answer 1

Python 2, 47 bytes

lambda l:l.sort(key=len)or l[1::2][::-1]+l[::2]

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Answer 2

R, 63 48 bytes

function(L)c(rev(o<-L[order(nchar(L))]),o)[!0:1]

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Sort by string lengths, then combine the reversed list with the sorted list, finally, take every 2nd element, starting at 1-based index 1.

Answer 3

Javascript 77 bytes

Takes input as an array of strings, outputs an arrow-sorted array of strings.

s=>s.sort((a,b)=>a.length-b.length).reduce((m,x,i)=>i%2?[...m,x]:[x,...m],[])

Explanation

s =>                                 // take input as an array of strings s
  s.sort((a,b)=>a.length-b.length)   // sort input by string length
  .reduce(                           // reduce
    (m,x,i)=>i%2?[...m,x]:[x,...m],  // if index is even, stick string x at the end of the memo
                                     // array, else at the beginning
    []                               // memo initialized to empty array
  )

Answer 4

Jelly, 9 8 bytes

LÞŒœm"-Ẏ

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LÞŒœṚ;¥/

is also 8 bytes.

Thanks to @EriktheOutgolfer and @JonathanAllan for both offering golfs to save a byte.

Answer 5

C# (Visual C# Interactive Compiler), 89 bytes

n=>(n=n.OrderBy(x=>x.Length)).Where((a,b)=>b%2>0).Reverse().Concat(n.Where((a,b)=>b%2<1))

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Answer 6

K (oK), 24 bytes

Solution:

x(<#:'x)(|&~w),&w:2!!#x:

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Explanation:

Generate the 6 4 2 0 1 3 5 sequence, use that to index into the ascending lengths of input, and use that to index into the original array:

x(<#:'x)(|&~w),&w:2!!#x: / the solution
                      x: / save input as x
                     #   / count (#) of x
                    !    / range 0 to ...
                  2!     / modulo 2
                w:       / save as w
               &         / indices where true
              ,          / join with
        (    )           / do this together
           ~w            / not (~) w
          &              / indices where true
         |               / reverse
 (     )                 / do this together
   #:'x                  / count (#:) of each (') x
  <                      / indices to sort ascending
x                        / index into x

Answer 7

Ruby, 51 bytes

->l{r=1;l.sort_by!(&:size).map{l[r-=2]||(l*2)[~r]}}

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Answer 8

J, 11 bytes

,~`,/@\:#&>

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We sort it down first.

Then we reduce the list form right to left, but alternating which side we put the new element on. Done.

Answer 9

05AB1E, 6 5 bytes

Saved 1 byte thanks to Kevin Cruijssen

I/O is a list of strings.
Link is modified for newline separated I/O for easier testing.

éι`Rì

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Explanation

é       # sort by length ascending
 ι      # uninterleave into 2 parts, both sorted ascending
   `    # push the 2 parts separately to the stack
    R   # reverse the second part
     ì  # and append it to the first

Answer 10

PHP, 144 141 bytes

function($a){usort($a,function($b,$c){return strlen($b)-strlen($c);});$e=[];foreach($a as$d)(array_.[unshift,push][++$i%2])($e,$d);return$e;}

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-3 bytes thanks to @Ismael Miguel!

Answer 11

PowerShell, 66 bytes

1..($a=$args|sort l*).count|?{$_%2}|%{$a[-$_];$x=,$a[-++$_]+$x};$x

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Takes input via splatting, which manifests on TIO as separate command-line arguments. sorts on the length, stores that into $a, and constructs a range from 1 up to the count of input strings. We then pull out only the odd ones ?{$_%2} and feed those into a loop |%{...}. Each iteration, we put the "last", then the "third from last", and so on onto the pipeline with $a[-$_]. Separately, we also accumulate into $x the "second from last", "fourth from last", etc. Out of the loop and the pipeline is flushed (so those elements are output) and then we output $x. In both instances, the default output gives us newlines between items automatically.

Answer 12

MATLAB, 87 bytes

function f(y);[B,I]=sort(cellfun(@(x)length(x),y));{y{flip(I(1:2:end))},y{I(2:2:end)}}'

Takes input as cell array of strings, outputs column of strings (not sure if that's legal)

> s = {'qweq qwe qw','qweqw','12132132131231231','asdasdasda','qwe','w'};
> f(s)
> >> 
> ans =
> 
>   6×1 cell array
> 
>     {'qweq qwe qw'      }
>     {'qweqw'            }
>     {'qwe'              }
>     {'1234'             }
>     {'asdasdasda'       }
>     {'12132132131231231'}

PS: Thanks Sanchises for pointing to a bug with odd-length inputs

Answer 13

APL (Dyalog Unicode), 18 bytes^SBCS

{⍵[⍋-@(2∘|)⍋⍋≢¨⍵]}

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Fixed the bug thanks to @ngn.

Explanation:

{⍵[⍋-@(2∘|)⍋⍋≢¨⍵]}
{                } ⍝ Function. Takes a single argument: ⍵, list of strings
             ≢¨⍵   ⍝ The length of each element in the list
           ⍋⍋      ⍝ Sort the lengths
    -@(2∘|)        ⍝ At (@) elements divisible by 2 (|), negate (-)
                   ⍝     gives -1 2 -3 4 -5
   ⍋               ⍝ Sort this list again, gives the indices of that list ^ sorted
 ⍵[             ]  ⍝ Use these indices to index into the argument

---

¹

Answer 14

APL+WIN, 31 38 bytes

See Adams comment

⊃n[(⍳⍴n)~a],⌽n[a←2×⍳⌊.5×⍴n←n[⍒∊⍴¨n←⎕]]

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Prompts for a nested vector of strings

Answer 15

Retina, 26 bytes

N$`
$.&
*\,2,^A`.+
,2,G`.+

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N$`
$.&

Sort the lines in ascending order of length ($.& returns the length of the line).

*\,2,^A`.+

Temporarily delete alternate lines and output the remaining lines in reverse order.

,2,G`.+

Keep the only lines that were temporarily deleted and output them.

Answer 16

Japt, 8 bytes

ñÊó g0_w

-3 bytes thanks to Shaggy!

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Answer 17

Gaia, 10 bytes

el∫v:v+2%ụ

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e		| eval as Gaia code (list of strings)
 l∫		| ∫ort by lengths (ascending)
   v:v		| reverse, dup, reverse
      +		| concatenate lists
       2%	| take every other element
         ụ	| join by newlines and output

Answer 18

PowerShell, 49 bytes

$args|sort l*|sort{$_.Length*($global:x=-$x*2+1)}

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The double distillation.

Answer 19

T-SQL, 84 bytes

Input is a table variable

SELECT a FROM(SELECT*,row_number()over(order by len(a))r
FROM @)x order by(r%2-.5)*r

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Answer 20

Perl 6, 31 bytes

*.sort(&chars).sort:{$++%2*$--}

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Sort by string length, then by static sequence 0, -1, 0, -3, 0, -5, ...

Answer 21

Javascript 95 Bytes

s=>s.sort((x,y)=>x.length-y.length).reduce((a,e,i)=>{i%2?a.push(e):a.unshift(e);return a;},[]);

Answer 22

C (gcc), 136 128 bytes

S(a,b)int**a,**b;{a=strlen(*b)-strlen(*a);}f(l,s,o,i,b,e)int**s,**o;{qsort(s,l,8,S);e=l-1;for(i=b=0;i-l;)o[i++%2?b++:e--]=s[i];}

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-8 bytes thanks to ceilingcat.

The function f is the solution. It takes the number of strings, the strings themselves, and the output buffer as arguments (plus four more used internally).

Answer 23

Red, 116 101 bytes

func[b][sort/compare b func[x y][(length? x)> length? y]collect[forall b[keep take b]keep reverse b]]

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Answer 24

perl 5 (-p0777F/\n/ -M5.01), 59 bytes

for$x(sort{$b=~y///c-length$a}@F){--$|?$\="$x
".$\:say$x}}{

TIO

Answer 25

Japt, 8 bytes

Input as an array of lines, output as an array of 2 arrays of lines, one for each half of the list.

ñÊó
hUÎÔ

Try it (Additional code to allow for I/O as newline separated string)

ñÊó      :Implicit input of array U
ñ        :Sort by
 Ê       :  Length
  ó      :Uninterleave

hUÎÔ     :Newline reassigns to U
h        :Set the first element in U to
 UÎ      :  The first element in U
   Ô     :  Reversed

Answer 26

Haskell, 104 96 bytes

import Data.List
f s=splitAt((length s+1)`div`2)s
g=sortOn length
h(x,y)=reverse(g x)++g y
z=h.f

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