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Good Evening Golfers!

Your challenge is to completely unsort a series of numbers.


Exactly 100 integers will be fed to your program. Your program may accept the input either as a file, or via stdin. Each integer will be separated by a newline character.

Those 100 integers will range from the minimal to the maximal values of a signed integer in your chosen language.

There will be no duplicate values. The values may be ordered, unordered or partially ordered - your program should be able to handle each case.


The output must be each of the 100 integers, completely unsorted, each separated by a newline character. The output may be via stdout, or to a file.

Completely Unsorted means that no value is adjacent to any value which it would be adjacent to if the list were completely sorted in an ordered sequence.


Pure code-golf. 1 point per character, and lowest score wins. There is a bonus of -100 for any solution using no built in or library sorting functions. There is a bonus of -20 for any solutions using no built in random number functions.

I have tried to define this question as completely as possible. If you have any questions, please ask. If you have any comments on how I could do better next time, please let me know.


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There are exactly 100 integers input, and there are no duplicate values (see under "Input") – lochok Oct 24 '12 at 8:54
Right you are, didn't spot that. – Strigoides Oct 24 '12 at 9:01
It's not a duplicate as such, but it's not very different to… – Peter Taylor Oct 24 '12 at 11:10
So many clever responses! I'll select shortest answer on Oct 31 at 8:10-Zulu – lochok Oct 28 '12 at 11:55

12 Answers 12

up vote 8 down vote accepted

GolfScript (score 27 - 120 = -93)


Note: that $ is referencing an element on the stack. There is sorting, but it's done with an manually coded bubble sort.

Thanks to Howard, for -90 => -92; and Ilmari, who inspired -92 => -93.

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Credit for such a concise answer, but (forgive me, as I don't speak or understand GolfScript) - wouldn't the ^ disqualify it from the -100 bonus? – lochok Oct 24 '12 at 12:50
@lochok, the built-in sort function is $ - that's why I mentioned that the $ in the program aren't sorts (it's context-dependent). The majority of the program (28 of the 42 characters) defines the function ^; the first version, using the built-in sort, was only 14 characters. – Peter Taylor Oct 24 '12 at 12:55
Ahh - right. Thanks for the clarification! – lochok Oct 24 '12 at 13:02
You can save two chars with the following output loop: 2/{~p}%n*. – Howard Oct 26 '12 at 14:43
2/zip~+n* and .);\+2%n* also do the trick for the same number of chars as @Howard's version. Alas, I haven't managed to find anything shorter yet. – Ilmari Karonen Oct 26 '12 at 20:07

Python -26

(94-120): New, crude approach. Keep popping lowest elements into new list to get the elements sorted, then iterate:

exec't=t+[input()];'*N+'l+=[t.pop(t.index(min(t)))];'*N+'print l[i%N];i+=3;'*N

Python -13

(107-120): First approach: Removes four lowest elements at a time, then print these four in another order:

while l:
 for e in[b,d,a,c]:print e
share|improve this answer
t=l=[] and exec't+=[input()];'*100 would save you a few chars – quasimodo Oct 26 '12 at 16:48
also, you can use one exec statement for more than one loop. – quasimodo Oct 26 '12 at 17:33
@quasimodo I tried something like that, but with t=l=[] t and l point to the same object and it doesn't work. Skipping parentheses on exec is nice though. – daniero Oct 26 '12 at 19:31
Thanks for the 'One exec for more than one loop' :) – daniero Oct 26 '12 at 19:47
You could use t=t+[input()];, this creates a new object each time. And you can even do the print loop in the exec statement: ';i+=1;print l[i*3%100]'*100. – quasimodo Oct 27 '12 at 10:53

C: 11 (131 - 120)

The programm reads from stdin and does a simple insert sort, after that it prints the nth together with th n+50th number, like many of the other solutions.

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Mathematica -56 44 4 (95-120) = -25


This version relies on neither built-in functions for sorting lists, nor randomization functions.

Riffle[RotateLeft[#[[All, 2]], 2], #[[All, 1]]] &
[Partition[l //. {x___, a_, b_, y___} /; b < a :> {x, b, a, y}, 2]]
share|improve this answer
Is Sort not a built-in sort function? – Peter Taylor Oct 24 '12 at 22:56
You are correct! I missed the constraint about sort. – DavidC Oct 24 '12 at 23:20
I made a hand-rolled Sort. – DavidC Oct 25 '12 at 19:04

J, -63 (57-120) characters

Since everyone else is going down the self-written sort route...


Doesn't use any random number function, nor any built-in sort.

Uses a simple recursive selection sort to sort the input.

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Ruby 1.9, -59


Recursion! This one does in fact, unlike my previous Ruby attempts, unsort the list regardless of their original order.

p *(f=->l{l[1]&&f[l-m=l.minmax]+m||[]})[$<.map &:to_i].rotate

Previous attempts

Cute one-liner, now using builtin sort to work properly:

$<.map(&:to_i).sort.each_slice(4){|a,b,c,d|p b,d,a,c}

First one -- Didn't necessarily unsort the last 4 values:

l=$<.map &:to_i
48.times{l-=p *l.minmax}
p b,d,a,c
share|improve this answer
Your -72 solution assumes the list starts out sorted, which is not the case. – histocrat Dec 5 '13 at 19:14
Oops. Seems I didn't re-read the question thoroughly when I revisited this one. Will try to come up with something else. – daniero Dec 6 '13 at 8:28
@histocrat that should do it. – daniero Dec 11 '13 at 16:14

Python 2: 90 char

s=sorted(int(raw_input())for i in range(n))
for i in range(n):print s[(4*i+4*i/n)%n]

lazy attempt but just for starters

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Python 48 = (148 - 100)

from random import*
x=[input()for i in range(100)]
while any(abs(x[i]-x[i+1])>1 for i in range(99)):n=randint(1,99);x=x[n:]+x[:n]
for j in x:print j

Haven't tested this because it isn't guaranteed (or likely) to run in any reasonable amount of time, but should work in theory given infinite time.

share|improve this answer
x=map(input,['']*100) – ugoren Oct 26 '12 at 5:32
wow, I love that – scleaver Oct 29 '12 at 17:24
And I don't think you even need the extra []s, just any single character string. – job Nov 1 '12 at 17:24

Python 27 (147 - 100 - 20)

def S(L):
 for i in R(len(L)-1):
    if L[i]>L[i+1]:L[i:i+2]=[L[i+1],L[i]];S(L)
for i in R(100):print a[i/2+i%2*50]

Note: the spaces before if L[i]>... should be a tab but apparently show up as spaces in a code block.

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With R=range you could save 5 characters. – scleaver Oct 24 '12 at 19:18
a=map(input,['']*100) – ugoren Oct 26 '12 at 5:33

Perl 5: 95 - 120 = -25 chars

Counting the following command line:

perl -ne '$n=$_;splice@n,(grep{$n[$_]>$n}0..@n),0,$n}{print for map{@n[$_,$#n/2+$_+1]}0..$#n/2'
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Ruby: -50 (70 chars - 120)

I did the same as many other answers: iteratively remove the max and min from the input list and append them to the output. However, I realized that if the 2 numbers on either side of the median are themselves consecutive, the output will be incorrect (because those 2 consecutive numbers will appear together at the end of the output). To fix this, I rotate the "unsorted" list right by 1 element:

n=$*.map &:to_i;u=[];50.times{u+=n.minmax;n-=u.last 2};p *u.rotate(-1)

Or, to work with arbitrarily many inputs (using only 4 more characters):

n=$*.map &:to_i;u=[];(u+=n.minmax;n-=u.last 2)while n.any?;p *u.rotate(-1)

Note: Some fewer-char Ruby answers have already been posted, but those solutions did not address the median issue (and/or assumed a sorted input list).

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J 37 - 100 = -63


Uses no sort (though does use rank up) Uses random numbers.


({~?~@#)             NB. Randomizes the array
^: foobar ^:_        NB. as long as
foo =: +./@(1 = |)   NB. as any 1 == absolute value of
bar =: (2&(-/\))@/:  NB. differences between adjacent ranks
foobar =: foo@bar
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