Sorting a list of strings without using any built-in sort method

Question

The goal of this Code Golf is to create a program that sorts a list of strings (in ascending order), without using any built-in sort method (such as Array.Sort() in .NET, sort() in PHP, ...). Note that this restriction excludes using a built-in method that sorts an array descending, and then reversing the array.

Some details:

• Your program should prompt for input, and this input is a list of strings containing only ASCII lower-case alphabetic characters a-z, comma-separated without spaces. For example:

  code,sorting,hello,golf
  

• The output should be the given list of strings, but sorted in ascending order, still comma-separated without spaces. For example:

  code,golf,hello,sorting
  

Answer 1

GolfScript, 26 25 bytes

","/.,{{.2$<{\}*}*]}*","*

Straightfoward implementation of Bubble Sort.

Try it online in Web GolfScript.

How it works

","/     # Split the input string at commas.
.,       # Get the number of chunks.
{        # Do that many times:
  {      #   Reduce; for each element but the first:
    .2$< #     Push 1 if the last two strings are in descending order, 0 if not.
    {\}* #     Swap these strings that many times.
  }*]    #   Collect the strings dumped by reduce in an array.
}*       #
","*     # Join, separating by commas.

Answer 2

Ruby 76 54 51 chars

x=gets.scan /\w+/;$><<x.dup.map{x.delete(x.min)}*?,

Answer 3

k (16 chars)

Probably doesn't really live up to the spirit of the problem. In k, there is no built in sort operator. <x returns a list of indices of items in x in sorted order.

{x@<x}[","\:0:0]

Answer 4

SED, 135

s/.*/,&,!,abcdefghijklmnopqrstuvwxyz/;:;s/\(,\([^,]*\)\(.\)[^,]*\)\(.*\)\(,\2\(.\)[^,]*\)\(.*!.*\6.*\3\)/\5\1\4\7/;t;s/^,\(.*\),!.*/\1/

Based on my previous sorting entry

Answer 5

Ruby, 99 chars (Gnome sort)

a=gets.scan /\w+/
p=1
while a[p]
a[p]>a[p-1]?p+=2:(a[p],a[p-1]=a[p-1],a[p])
p-=1if p>1
end
$><<a*?,

This just barely beats my bubble sort implementation:

Ruby, 110 104 101 chars (Bubble sort)

s=gets.scan /\w+/
(z=s.size).times{(0..(z-2)).map{|i|s[i],s[i+1]=s[i+1],s[i]if s[i]>s[i+1]}}
$><<s*?,

This does list.length iterations, because worst-case scenario takes list.length - 1 iterations and one more really doesn't matter, and saves 2 chars.

Just for fun, a Quicksort version:

Ruby, 113 chars (Quicksort)

q=->a{if a[1]
p=a.shift
l=[]
g=[]
a.map{|x|(x>p ?g:l).push x}
q[l]+[p]+q[g]
else
a
end}
$><<q[gets.scan /\w+/]*?,

Answer 6

Haskell, 141

import Data.List
m=minimum
s[]=[]
s l=m l:s(l\\[m l])
t[]=[]
t s=let(a,b)=span(/=',')s in a:t(drop 1 b)
main=interact$intercalate",".s.t.init

At least it’s… sort of efficient.

Answer 7

vba, 165

Sub q()
c=","
s=InputBox("?")
Z=Split(s, c)
t=UBound(Z)
For i=1 To t-1
For j=i To t
If Z(i)>Z(j) Then a=Z(i):Z(i)=Z(j):Z(j)=a
Next
Next
Debug.Print Join(Z,c)
End Sub

Answer 8

Scala, 122 bytes

As a one-liner (88 bytes):

.permutations.filter(_.sliding(2).map(w=>w(0)<w.last).fold(true)((a,b)=>a&&b)).toSeq(0)

(it will sort a list by just doing list.permutations.fil... )

As a program (122 bytes):

println(readLine.split(",").toSeq.permutations.filter(_.sliding(2).map(w=>w(0)<w.last).fold(true)((a,b)=>a&&b)).toSeq(0))

A longer version if you want it to read from stdin.

This iterate over all the permutations of the given list until it stumble on a sorted one. It's not fast as it takes about 12 seconds to sort a 10 elements list and well over a minute for a 11 elements one.

[Edit] items need to be unique or < can be replaced by <=. Also, sorry for necro.

Answer 9

javascript 128

a=prompt().split(',');b=[];for(i in a){b.push(a[i]);k=0;for(j in b){j=k;b[j]>a[i]?[c=b[j],b.splice(j,1),b.push(c)]:k++}}alert(b)

DEMO fiddle.

i am looking for a way to eliminate b.

Answer 10

PHP 83 bytes

<?for($x=fgetcsv(STDIN);$x;)${$x[0]>min($x)?x:a}[]=array_shift($x)?><?=join(~Ó,$a);

An O(n³) implementation of a selection sort. The Ó is character 211; a bit-inverted comma.

Sample usage:

$ more in.dat
code,sorting,hello,golf

$ php list-sort.php < in.dat
code,golf,hello,sorting

Answer 11

Python 3 (80 chars)

l=input().split(',')
m=[]
while l:m+=[l.pop(l.index(min(l)))]
print(','.join(m))

Here is a variation of the while-statement that is of equal length:

while l:x=min(l);m+=[x];l.remove(x)

Answer 12

Mathematica 66 56

Row[#[[Ordering@#]]&[InputString[]~StringSplit~","],","]

Some other solutions without the build-in symbol Ordering:

Bogosort: 84 74

NestWhile[RandomSample,InputString[]~StringSplit~",",!OrderedQ@#&]~Row~","

Bubble Sort: 93 83

Row[InputString[]~StringSplit~","//.{x___,i_,j_,y___}/;j~Order~i==1:>{x,j,i,y},","]

Another solution as inefficient as bogosort: 82 72

#~Row~","&/@Permutations[InputString[]~StringSplit~","]~Select~OrderedQ;

Answer 13

Python 3.5+, 73 bytes

This takes inspiration from Steven Rumbalski's answer but uses list comprehension instead of a while loop; the number of iterations comes from the copied list l which is the reason this requires additional unpacking generalizations and Python 3.5

l=input().split(',');print(*[l.pop(l.index(min(l)))for _ in[*l]],sep=',')

Answer 14

R

Bubble Sort: 122 118 characters

a=scan(,"",sep=",");h=T;while(h){h=F;for(i in 1:(length(a)-1)){j=i+1;if(a[i]>a[j]){a[j:i]=a[i:j];h=T}}};cat(a,sep=",")

Bogosort: 100 characters

a=scan(,"",sep=",");while(any(apply(embed(a,2),1,function(x)x[1]<x[2]))){a=sample(a)};cat(a,sep=",")

Answer 15

Perl, 159

perl -F"," -lape "$m=$m<length()?length():$m for@F;$_{10**(2*$m)*sprintf'0.'.'%02d'x$m,map-96+ord,split//}=$_ for@F;$_=join',',map$_{$_+0},grep exists$_{$_+0},'0'.1..'0'.10**100"

This never stood a chance to win, but decided to share it because I liked the logic even if it's a mess :) The idea behind it, is to convert each word into an integer (done using the ord function), we save the number as a key in a hash and the string as a value, and then we iterate increasingly through all integers (1..10**100 in this case) and that way we get our strings sorted.

WARNING: Don't run this code on your computer, since it loops through trillions+ of integers. If you want to test it, you can lower the upper range limit and input non-lengthy strings. If for any reason this is against the rules, please let me know and I'll delete the entry!

Answer 16

JS: 107 chars - Bubble Sort

a=prompt().split(/,/);for(i=a.length;i--;)for(j=0;j<i;)a[j]>a[j+1]?[b=a[j],a[j]=a[++j],a[j]=b]:j++;alert(a)

I looked at @tryingToGetProgrammingStraight's answer and tried to improve it, but ended up implementing it slightly differently.

Answer 17

Ceylon (Bogosort), 119

String s(String i)=>",".join([*i.split(','.equals)].permutations.select((p)=>!any{for([x,y]in p.paired)y<x})[0]else[]);

Try it online!

I found the permutations method and thus ended up with Bogosort (a non-random variant).

Formatted and commented:

// a function `s` mapping a String `i` to a String
String s(String i) =>
    // the end result is created by joining the iterable in (...).
    ",".join(
        // take the input, split it on commas, make the result a sequence.
        [*
            i.split(','.equals)   // → {String+}
           ]                      // → [String+]
        // get the iterable of all permutations of this sequence.
        // Yes, this is an iterable of O(n!) sequences (though likely
        // lazily computed, we don't need all in memory at once).
        .permutations              // → {[String+]*}
        // filter this iterable for ordered sequences.
        // Using select instead of filter makes this
        // eager instead of lazy, so we are actually iterating
        // through all n! sequences, and storing the ordered
        // ones. (All of those are equal.)
        .select(
            // this is our function to check whether this sequence
            // is ordered in ascending order.
            (p)=>
               // return if none of the following iterable of booleans is true.
                !any {
                   // This is a for-comprehension. Inside an named argument list
                   // (what we have here, although there is no name) for a
                   // function which wants an iterable, this becomes an iterable,
                   // lazily built from the existing iterable p.paired,
                   // which is just an iterable with all pairs of subsequent
                   // elements.
                      for([x,y] in p.paired)
                        // for each such pair, we evaluate this expression, which
                        // is true when the sequence is not ordered correctly.
                           y < x         // → Boolean
                        // → {Boolean*}
                    }  //   → Boolean
                 //  → Boolean([String+])
               ) // → [[String+]*]
         // we now have a sequence of (correctly sorted) sequences.
         // just take the first one.
         // If we had used `.filter` before, this would have to be `.first`.
               [0]    // → [String+]|Null
         // in case this is null, which can only happen if the original array was
         // empty, so there were no permutations, just use the empty sequence
         //  again. (Actually, split never returns an empty array, so this can't
         //  happen, but the type checker can't know that.)
               else []    // → [String*]
    // so that is what we pass to the join method.
        )   // → String
    ;

Without the formatting and parsing it becomes just 90 bytes:

String[]s(String[]i)=>i.permutations.select((p)=>!any{for([x,y]in p.paired)y<x})[0]else[];

Try it online!

Answer 18

Perl 5, 77 bytes

map{$F[$_]gt$F[$_+1]&&(@F[$_,$_+1]=@F[$_+1,$_])for 0..@F-2}@F;$_=join',',"@F"

Try it online!

Simple bubble sort.

Answer 19

ruby -plaF, , 70 bytes

o=[]
$F.map{|s|i=o;s.bytes{|b|i=i[b]=[*i[b]]};i[0]=s<<?,}
$_=o*''
chop

O(n), if you pretend that resizing and compacting an array is free (it is very not free).

We create a deeply and unevenly nested array o by putting a string with bytes b₁,b₂...b_n into the array at position o[b₁][b₂]...[b_n]. The result looks like [,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,["a,",,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, [,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ["abc,"], ["abd,"], ["abe,"]], ["ac,"], ["ad,"]],, ["c,"]]

Then we flatten and output it.

Answer 20

Reusing my own answer on Sort an Integer List

Tcl, 211 bytes

set L [split [gets stdin] ,]
set i 0
time {incr j;set x 0;while \$x<$i {if \"[lindex $L $i]"<"[lindex $L $x]" {set L [lreplace [linsert $L $x [lindex $L $i]] $j $j]};incr x};incr i} [llength $L]
puts [join $L ,]

Try it online!

Answer 21

Java, 134 bytes

A method that implements Gnome Sort.

void s(String[]a){int m=a.length-1,i=0;while(i<m){while(i>=0&&a[i].compareTo(a[i+1])>0){String t=a[i];a[i]=a[i+1];a[i+1]=t;i--;}i++;}}

Answer 22

Swift, 101 bytes

func s(a:[String])->[String]{return a.count<2 ? a:(s(a.filter{$0<a[0]})+[a[0]]+s(a.filter{$0>a[0]}))}

Ungolfed:

//quicksort
func sort(a:[String]) -> [String]
{
    //return the array if its length is less than or equal to 1
    if a.count <= 1
    {
        return a
    }
    //choose the first element as pivot
    let pivot = a[0]
    //retrieve all elements less than the pivot
    let left = a.filter{ $0 < pivot }
    //retrieve all elements greater than the pivot
    let right = a.filter{ $0 > pivot }
    //sort the left partition, append a new array containing the pivot,
    //append the sorted right partition
    return sort(left) + Array<String>(arrayLiteral: pivot) + sort(right)
}

Answer 23

, 24 chars / 30 bytes (noncompetitive)

ï⇔Ĕ⍪;↻ïꝈ)ΞÿѨŗ ï,⇀$≔МƵï;Ξ

Try it here (Firefox only).

Using selection sort!

Explanation

ï⇔Ĕ⍪;↻ïꝈ)ΞÿѨŗ ï,⇀$≔МƵï;Ξ // implicit: ï=input, Ξ=[]
ï⇔Ĕ⍪;                    // split ï along commas and set it to ï
     ↻ïꝈ)                // while ï's length > 0
         Ξÿ              // push to Ξ:
           Ѩŗ ï,⇀$≔МƵï;  // removed minimum item(s) from ï using builtin
                       Ξ // get sorted array

Basically recursively removes and pushes the minimum from the input to another array.