⚠️ Warning: This is a draft ⚠️
This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.
{{task|Sorting Algorithms}} {{Sorting Algorithm}} {{Wikipedia|Counting sort}}
;Task: Implement the [[wp:Counting sort|Counting sort]]. This is a way of sorting integers when the minimum and maximum value are known.
Pseudocode: '''function''' ''countingSort''(array, min, max): count: '''array of''' (max - min + 1) '''elements''' '''initialize''' count '''with''' 0 '''for each''' number '''in''' array '''do''' count[number - min] := count[number - min] + 1 '''done''' z := 0 '''for''' i '''from''' min '''to''' max '''do''' '''while''' ( count[i - min] > 0 ) '''do''' array[z] := i z := z+1 count[i - min] := count[i - min] - 1 '''done''' '''done'''
The ''min'' and ''max'' can be computed apart, or be known ''a priori''.
'''Note''': we know that, given an array of integers, its maximum and minimum values can be always found; but if we imagine the worst case for an array that can hold up to 32 bit integers, we see that in order to hold the counts, an array of up to '''232''' elements may be needed. I.E.: we need to hold a count value up to '''232-1''', which is a little over 4.2 Gbytes. So the counting sort is more practical when the range is (very) limited, and minimum and maximum values are known ''a priori''. (The use of ''sparse arrays'' minimizes the impact of the memory usage, as well as removing the need of having to know the minimum and maximum values ''a priori''.)
ActionScript
function countingSort(array:Array, min:int, max:int)
{
var count:Array = new Array(array.length);
for(var i:int = 0; i < count.length;i++)count[i]=0;
for(i = 0; i < array.length; i++)
{
count[array[i]-min] ++;
}
var j:uint = 0;
for(i = min; i <= max; i++)
{
for(; count[i-min] > 0; count[i-min]--)
array[j++] = i;
}
return array;
}
Ada
Given that we know the range of data, the problem really reduces to initializing the array to the ordered range of values. The input order is irrelevant.
with Ada.Text_Io; use Ada.Text_Io;
procedure Counting_Sort is
type Data is array (Integer range <>) of Natural;
procedure Sort(Item : out Data) is
begin
for I in Item'range loop
Item(I) := I;
end loop;
end Sort;
Stuff : Data(1..140);
begin
Sort(Stuff);
for I in Stuff'range loop
Put(Natural'Image(Stuff(I)));
end loop;
New_Line;
end Counting_Sort;
Output
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
ALGOL 68
{{trans|C}}
{{works with|ALGOL 68|Standard - no extensions to language used}}
{{works with|ALGOL 68G|Any - tested with release mk15-0.8b.fc9.i386}}
{{works with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release 1.8.8d.fc9.i386}}
PROC counting sort mm = (REF[]INT array, INT min, max)VOID:
(
INT z := LWB array - 1;
[min:max]INT count;
FOR i FROM LWB count TO UPB count DO count[i] := 0 OD;
FOR i TO UPB array DO count[ array[i] ]+:=1 OD;
FOR i FROM LWB count TO UPB count DO
FOR j TO count[i] DO array[z+:=1] := i OD
OD
);
PROC counting sort = (REF[]INT array)VOID:
(
INT min, max;
min := max := array[LWB array];
FOR i FROM LWB array + 1 TO UPB array DO
IF array[i] < min THEN
min := array[i]
ELIF array[i] > max THEN
max := array[i]
FI
OD
);
# Testing (we suppose the oldest human being is less than 140 years old). #
INT n = 100;
INT min age = 0, max age = 140;
main:
(
[n]INT ages;
FOR i TO UPB ages DO ages[i] := ENTIER (random * ( max age + 1 ) ) OD;
counting sort mm(ages, min age, max age);
FOR i TO UPB ages DO print((" ", whole(ages[i],0))) OD;
print(new line)
)
Sample output:
0 1 2 3 3 4 4 5 6 7 8 9 9 10 11 12 15 18 18 19 21 21 22 27 33 35 36 38 38 38 38 39 40 40 41 43 44 53 54 55 57 57 58 59 59 60 60 60 60 61 62 64 65 66 67 68 70 71 78 79 82 83 84 84 87 87 88 88 88 89 89 92 93 93 97 98 99 99 100 107 109 114 115 115 118 122 126 127 127 129 129 130 131 133 134 136 136 137 139 139
AutoHotkey
contributed by Laszlo on the ahk [http://www.autohotkey.com/forum/post-276465.html#276465 forum]
MsgBox % CountingSort("-1,1,1,0,-1",-1,1)
CountingSort(ints,min,max) {
Loop % max-min+1
i := A_Index-1, a%i% := 0
Loop Parse, ints, `, %A_Space%%A_Tab%
i := A_LoopField-min, a%i%++
Loop % max-min+1 {
i := A_Index-1, v := i+min
Loop % a%i%
t .= "," v
}
Return SubStr(t,2)
}
BASIC256
# counting sort
n = 10
dim test(n)
test = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}
mn = -31
mx = 782
dim cnt(mx - mn + 1) # count is a reserved string function name
# seems initialized as 0
# for i = 1 to n
# print cnt[i]
# next i
# sort
for i = 0 to n-1
cnt[test[i] - mn] = cnt[test[i] - mn] + 1
next i
# output
print "original"
for i = 0 to n-1
print test[i] + " ";
next i
print
print "ordered"
for i = 0 to mx - mn
if 0 < cnt[i] then # for i = k to 0 causes error
for k = 1 to cnt[i]
print i + mn + " ";
next k
endif
next i
print
BBC BASIC
DIM test%(9)
test%() = 4, 65, 2, -31, 0, 99, 2, 83, 782, 1
PROCcountingsort(test%(), -31, 782)
FOR i% = 0 TO 9
PRINT test%(i%) ;
NEXT
PRINT
END
DEF PROCcountingsort(a%(), l%, h%)
LOCAL i%, z%, c%()
DIM c%(h% - l%)
FOR i% = 0 TO DIM(a%(),1)
c%(a%(i%) - l%) += 1
NEXT
FOR i% = l% TO h%
WHILE c%(i% - l%)
a%(z%) = i%
z% += 1
c%(i% - l%) -= 1
ENDWHILE
NEXT
ENDPROC
'''Output:'''
-31 0 1 2 2 4 65 83 99 782
C
#include <stdio.h>
#include <stdlib.h>
void counting_sort_mm(int *array, int n, int min, int max)
{
int i, j, z;
int range = max - min + 1;
int *count = malloc(range * sizeof(*array));
for(i = 0; i < range; i++) count[i] = 0;
for(i = 0; i < n; i++) count[ array[i] - min ]++;
for(i = min, z = 0; i <= max; i++) {
for(j = 0; j < count[i - min]; j++) {
array[z++] = i;
}
}
free(count);
}
void min_max(int *array, int n, int *min, int *max)
{
int i;
*min = *max = array[0];
for(i=1; i < n; i++) {
if ( array[i] < *min ) {
*min = array[i];
} else if ( array[i] > *max ) {
*max = array[i];
}
}
}
Testing (we suppose the oldest human being is less than 140 years old).
#define N 100
#define MAX_AGE 140
int main()
{
int ages[N], i;
for(i=0; i < N; i++) ages[i] = rand()%MAX_AGE;
counting_sort_mm(ages, N, 0, MAX_AGE);
for(i=0; i < N; i++) printf("%d\n", ages[i]);
return EXIT_SUCCESS;
}
C++
#include <iostream>
#include <time.h>
//------------------------------------------------------------------------------
using namespace std;
//------------------------------------------------------------------------------
const int MAX = 30;
//------------------------------------------------------------------------------
class cSort
{
public:
void sort( int* arr, int len )
{
int mi, mx, z = 0; findMinMax( arr, len, mi, mx );
int nlen = ( mx - mi ) + 1; int* temp = new int[nlen];
memset( temp, 0, nlen * sizeof( int ) );
for( int i = 0; i < len; i++ ) temp[arr[i] - mi]++;
for( int i = mi; i <= mx; i++ )
{
while( temp[i - mi] )
{
arr[z++] = i;
temp[i - mi]--;
}
}
delete [] temp;
}
private:
void findMinMax( int* arr, int len, int& mi, int& mx )
{
mi = INT_MAX; mx = 0;
for( int i = 0; i < len; i++ )
{
if( arr[i] > mx ) mx = arr[i];
if( arr[i] < mi ) mi = arr[i];
}
}
};
//------------------------------------------------------------------------------
int main( int argc, char* argv[] )
{
srand( time( NULL ) ); int arr[MAX];
for( int i = 0; i < MAX; i++ )
arr[i] = rand() % 140 - rand() % 40 + 1;
for( int i = 0; i < MAX; i++ )
cout << arr[i] << ", ";
cout << endl << endl;
cSort s; s.sort( arr, MAX );
for( int i = 0; i < MAX; i++ )
cout << arr[i] << ", ";
cout << endl << endl;
return system( "pause" );
}
//------------------------------------------------------------------------------
{{out}}
105, -21, 20, 5, 3, 25, 101, 116, 82, 5, 88, 80, -9, 26, 62, 118, 131, -31, 3, 3
8, 40, -6, 46, 90, 7, 59, 104, 76, 12, 79,
-31, -21, -9, -6, 3, 3, 5, 5, 7, 12, 20, 25, 26, 38, 40, 46, 59, 62, 76, 79, 80,
82, 88, 90, 101, 104, 105, 116, 118, 131,
Alternate version
Uses C++11. Compile with g++ -std=c++11 counting.cpp
#include <algorithm>
#include <iterator>
#include <iostream>
#include <vector>
template<typename ForwardIterator> void counting_sort(ForwardIterator begin,
ForwardIterator end) {
auto min_max = std::minmax_element(begin, end);
if (min_max.first == min_max.second) { // empty range
return;
}
auto min = *min_max.first;
auto max = *min_max.second;
std::vector<unsigned> count((max - min) + 1, 0u);
for (auto i = begin; i != end; ++i) {
++count[*i - min];
}
for (auto i = min; i <= max; ++i) {
for (auto j = 0; j < count[i - min]; ++j) {
*begin++ = i;
}
}
}
int main() {
int a[] = {100, 2, 56, 200, -52, 3, 99, 33, 177, -199};
counting_sort(std::begin(a), std::end(a));
copy(std::begin(a), std::end(a), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
}
Output:
-199 -52 2 3 33 56 99 100 177 200
C#
using System;
using System.Linq;
namespace CountingSort
{
class Program
{
static void Main(string[] args)
{
Random rand = new Random(); // Just for creating a test array
int[] arr = new int[100]; // of random numbers
for (int i = 0; i < 100; i++) { arr[i] = rand.Next(0, 100); } // ...
int[] newarr = countingSort(arr, arr.Min(), arr.Max());
}
private static int[] countingSort(int[] arr, int min, int max)
{
int[] count = new int[max - min + 1];
int z = 0;
for (int i = 0; i < count.Length; i++) { count[i] = 0; }
for (int i = 0; i < arr.Length; i++) { count[arr[i] - min]++; }
for (int i = min; i <= max; i++)
{
while (count[i - min]-- > 0)
{
arr[z] = i;
z++;
}
}
return arr;
}
}
}
Common Lisp
Straightforward implementation of counting sort. By using [http://www.lispworks.com/documentation/HyperSpec/Body/f_map.htm map]
and [http://www.lispworks.com/documentation/HyperSpec/Body/f_map_in.htm map-into]
, counting sort can work efficiently on both lists and vectors. The closure given as the second argument to map-into
returns the sorted elements of sequence. Because map-into
will only call the function as many times as necessary to re-populate sequence, there is no need for bounds checking. counts
is declared to have dynamic-extent and so a compiler might stack allocate it.
(defun counting-sort (sequence &optional (min (reduce #'min sequence))
(max (reduce #'max sequence)))
(let ((i 0)
(counts (make-array (1+ (- max min)) :initial-element 0
:element-type `(integer 0 ,(length sequence)))))
(declare (dynamic-extent counts))
(map nil (lambda (n) (incf (aref counts (- n min)))) sequence)
(map-into sequence (lambda ()
(do () ((plusp (aref counts i)))
(incf i))
(decf (aref counts i))
(+ i min)))))
D
import std.stdio, std.algorithm;
void countingSort(int[] array, in size_t min, in size_t max)
pure nothrow {
auto count = new int[max - min + 1];
foreach (number; array)
count[number - min]++;
size_t z = 0;
foreach (i; min .. max + 1)
while (count[i - min] > 0) {
array[z] = i;
z++;
count[i - min]--;
}
}
void main() {
auto data = [9, 7, 10, 2, 9, 7, 4, 3, 10, 2, 7, 10, 2, 1, 3, 8,
7, 3, 9, 5, 8, 5, 1, 6, 3, 7, 5, 4, 6, 9, 9, 6, 6,
10, 2, 4, 5, 2, 8, 2, 2, 5, 2, 9, 3, 3, 5, 7, 8, 4];
int dataMin = reduce!min(data);
int dataMax = reduce!max(data);
countingSort(data, dataMin, dataMax);
assert(isSorted(data));
}
E
Straightforward implementation, no particularly interesting characteristics.
def countingSort(array, min, max) {
def counts := ([0] * (max - min + 1)).diverge()
for elem in array {
counts[elem - min] += 1
}
var i := -1
for offset => count in counts {
def elem := min + offset
for _ in 1..count {
array[i += 1] := elem
}
}
}
? def arr := [34,6,8,7,4,3,56,7,8,4,3,5,7,8,6,4,4,67,9,0,0,76,467,453,34,435,37,4,34,234,435,3,2,7,4,634,534,735,5,4,6,78,4].diverge() # value: [34, 6, 8, 7, 4, 3, 56, 7, 8, 4, 3, 5, 7, 8, 6, 4, 4, 67, 9, 0, 0, 76, 467, 453, 34, 435, 37, 4, 34, 234, 435, 3, 2, 7, 4, 634, 534, 735, 5, 4, 6, 78, 4].diverge() ? countingSort(arr, 0, 735) ? arr # value: [0, 0, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 34, 34, 34, 37, 56, 67, 76, 78, 234, 435, 435, 453, 467, 534, 634, 735].diverge() ``` ## Eiffel ```Eiffel class COUNTING_SORT feature sort (ar: ARRAY [INTEGER]; min, max: INTEGER): ARRAY [INTEGER] -- Sorted Array in ascending order. require ar_not_void: ar /= Void lowest_index_zero: ar.lower = 0 local count: ARRAY [INTEGER] i, j, z: INTEGER do create Result.make_empty Result.deep_copy (ar) create count.make_filled (0, 0, max - min) from i := 0 until i = Result.count loop count [Result [i] - min] := count [Result [i] - min] + 1 i := i + 1 end z := 0 from i := min until i > max loop from j := 0 until j = count [i - min] loop Result [z] := i z := z + 1 j := j + 1 end i := i + 1 end ensure Result_is_sorted: is_sorted (Result) end feature {NONE} is_sorted (ar: ARRAY [INTEGER]): BOOLEAN --- Is 'ar' sorted in ascending order? require ar_not_empty: ar.is_empty = False local i: INTEGER do Result := True from i := ar.lower until i = ar.upper loop if ar [i] > ar [i + 1] then Result := False end i := i + 1 end end end ``` TEST: ```Eiffel class APPLICATION create make feature make do create test.make_filled (0, 0, 5) test [0] := -7 test [1] := 4 test [2] := 2 test [3] := 6 test [4] := 1 test [5] := 3 io.put_string ("unsorted:%N") across test as t loop io.put_string (t.item.out + "%T") end io.new_line io.put_string ("sorted:%N") create count test := count.sort (test, -7, 6) across test as ar loop io.put_string (ar.item.out + "%T") end end count: COUNTING_SORT test: ARRAY [INTEGER] end ``` {{out}} ```txt unsorted: -7 4 2 6 1 3 sorted: -7 1 2 3 4 6 ``` ## Elena ELENA 4.x : ```elena import extensions; import system'routines; extension op { countingSort() = self.clone().countingSort(self.MinimalMember, self.MaximalMember); countingSort(int min, int max) { int[] count := new int[](max - min + 1); int z := 0; count.populate:(int i => 0); for(int i := 0, i < self.Length, i += 1) { count[self[i] - min] := count[self[i] - min] + 1 }; for(int i := min, i <= max, i += 1) { while (count[i - min] > 0) { self[z] := i; z += 1; count[i - min] := count[i - min] - 1 } } } } public program() { var list := new Range(0, 10).selectBy:(i => randomGenerator.eval(10)).toArray(); console.printLine("before:", list.asEnumerable()); console.printLine("after :", list.countingSort().asEnumerable()) } ``` {{out}} ```txt before:6,5,3,1,0,0,7,7,8,2 after :0,0,1,2,3,5,6,7,7,8 ``` ## Elixir {{works with|Elixir|1.1}} ```elixir defmodule Sort do def counting_sort([]), do: [] def counting_sort(list) do {min, max} = Enum.min_max(list) count = Tuple.duplicate(0, max - min + 1) counted = Enum.reduce(list, count, fn x,acc -> i = x - min put_elem(acc, i, elem(acc, i) + 1) end) Enum.flat_map(min..max, &List.duplicate(&1, elem(counted, &1 - min))) end end IO.inspect Sort.counting_sort([1,-2,-3,2,1,-5,5,5,4,5,9]) ``` {{out}} ```txt [-5, -3, -2, 1, 1, 2, 4, 5, 5, 5, 9] ``` ## Fortran {{works with|Fortran|95 and later}} ```fortran module CountingSort implicit none interface counting_sort module procedure counting_sort_mm, counting_sort_a end interface contains subroutine counting_sort_a(array) integer, dimension(:), intent(inout) :: array call counting_sort_mm(array, minval(array), maxval(array)) end subroutine counting_sort_a subroutine counting_sort_mm(array, tmin, tmax) integer, dimension(:), intent(inout) :: array integer, intent(in) :: tmin, tmax integer, dimension(tmin:tmax) :: cnt integer :: i, z cnt = 0 ! Initialize to zero to prevent false counts FORALL (I=1:size(array)) ! Not sure that this gives any benefit over a DO loop. cnt(array(i)) = cnt(array(i))+1 END FORALL ! ! ok - cnt contains the frequency of every value ! let's unwind them into the original array ! z = 1 do i = tmin, tmax do while ( cnt(i) > 0 ) array(z) = i z = z + 1 cnt(i) = cnt(i) - 1 end do end do end subroutine counting_sort_mm end module CountingSort ``` Testing: ```fortran program test use CountingSort implicit none integer, parameter :: n = 100, max_age = 140 real, dimension(n) :: t integer, dimension(n) :: ages call random_number(t) ages = floor(t * max_age) call counting_sort(ages, 0, max_age) write(*,'(I4)') ages end program test ``` ## FreeBASIC ```freebasic ' FB 1.05.0 Win64 Function findMax(array() As Integer) As Integer Dim length As Integer = UBound(array) - LBound(array) + 1 If length = 0 Then Return 0 '' say If length = 1 Then Return array(LBound(array)) Dim max As Integer = LBound(array) For i As Integer = LBound(array) + 1 To UBound(array) If array(i) > max Then max = array(i) Next Return max End Function Function findMin(array() As Integer) As Integer Dim length As Integer = UBound(array) - LBound(array) + 1 If length = 0 Then Return 0 '' say If length = 1 Then Return array(LBound(array)) Dim min As Integer = LBound(array) For i As Integer = LBound(array) + 1 To UBound(array) If array(i) < min Then min = array(i) Next Return min End Function Sub countingSort(array() As Integer, min As Integer, max As Integer) Dim count(0 To max - min) As Integer '' all zero by default Dim As Integer number, z For i As Integer = LBound(array) To UBound(array) number = array(i) count(number - min) += 1 Next z = LBound(array) For i As Integer = min To max While count(i - min) > 0 array(z) = i z += 1 count(i - min) -= 1 Wend Next End Sub Sub printArray(array() As Integer) For i As Integer = LBound(array) To UBound(array) Print Using "####"; array(i); Next Print End Sub Dim array(1 To 10) As Integer = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1} '' using BBC BASIC example array Print "Unsorted : "; printArray(array()) Dim max As Integer = findMax(array()) Dim min As Integer = findMin(array()) countingSort array(), min, max Print "Sorted : "; printArray(array()) Print Print "Press any key to quit" Sleep ``` {{out}} ```txt Unsorted : 4 65 2 -31 0 99 2 83 782 1 Sorted : -31 0 1 2 2 4 65 83 99 782 ``` ## Go This version follows the task pseudocode above, with one more optimization. ```go package main import ( "fmt" "runtime" "strings" ) var a = []int{170, 45, 75, -90, -802, 24, 2, 66} var aMin, aMax = -1000, 1000 func main() { fmt.Println("before:", a) countingSort(a, aMin, aMax) fmt.Println("after: ", a) } func countingSort(a []int, aMin, aMax int) { defer func() { if x := recover(); x != nil { // one error we'll handle and print a little nicer message if _, ok := x.(runtime.Error); ok && strings.HasSuffix(x.(error).Error(), "index out of range") { fmt.Printf("data value out of range (%d..%d)\n", aMin, aMax) return } // anything else, we re-panic panic(x) } }() count := make([]int, aMax-aMin+1) for _, x := range a { count[x-aMin]++ } z := 0 // optimization over task pseudocode: variable c is used instead of // count[i-min]. This saves some unneccessary calculations. for i, c := range count { for ; c > 0; c-- { a[z] = i + aMin z++ } } } ``` This version follows the WP pseudocode. It can be adapted to sort items other than integers. ```go package main import ( "fmt" "runtime" "strings" ) var a = []int{170, 45, 75, -90, -802, 24, 2, 66} var aMin, aMax = -1000, 1000 func main() { fmt.Println("before:", a) countingSort(a, aMin, aMax) fmt.Println("after: ", a) } func countingSort(a []int, aMin, aMax int) { defer func() { if x := recover(); x != nil { // one error we'll handle and print a little nicer message if _, ok := x.(runtime.Error); ok && strings.HasSuffix(x.(error).Error(), "index out of range") { fmt.Printf("data value out of range (%d..%d)\n", aMin, aMax) return } // anything else, we re-panic panic(x) } }() // WP algorithm k := aMax - aMin // k is maximum key value. keys range 0..k count := make([]int, k+1) key := func(v int) int { return v - aMin } for _, x := range a { count[key(x)]++ } total := 0 for i, c := range count { count[i] = total total += c } output := make([]int, len(a)) for _, x := range a { output[count[key(x)]] = x count[key(x)]++ } copy(a, output) } ``` ## Groovy Solution: ```groovy def countingSort = { array -> def max = array.max() def min = array.min() // this list size allows use of Groovy's natural negative indexing def count = [0] * (max + 1 + [0, -min].max()) array.each { count[it] ++ } (min..max).findAll{ count[it] }.collect{ [it]*count[it] }.flatten() } ``` Test: ```groovy println countingSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]) println countingSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]) println countingSort([15,-3,0,-1,5,4,5,20,-8]) println countingSort([34,6,8,7,4,3,56,7,8,4,3,5,7,8,6,4,4,67,9,0,0,76,467,453,34,435,37,4,34,234,435,3,2,7,4,634,534,-735,5,4,6,78,4]) // slo-o-o-o-ow due to unnecessarily large counting array println countingSort([10000033,10000006,10000008,10000009,10000013,10000031,10000013,10000032,10000023,10000023,10000011,10000012,10000021]) ``` Output: ```txt [4, 12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99] [0, 1, 4, 5, 7, 8, 12, 14, 18, 20, 31, 33, 44, 62, 70, 73, 75, 76, 78, 81, 82, 84, 88] [-8, -3, -1, 0, 4, 5, 5, 15, 20] [-735, 0, 0, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 34, 34, 34, 37, 56, 67, 76, 78, 234, 435, 435, 453, 467, 534, 634] [10000006, 10000008, 10000009, 10000011, 10000012, 10000013, 10000013, 10000021, 10000023, 10000023, 10000031, 10000032, 10000033] ``` ## Haskell We use lists for input and output rather than arrays, since lists are used more often in Haskell. ```haskell import Data.Array countingSort :: (Ix n) => [n] -> n -> n -> [n] countingSort l lo hi = concatMap (uncurry $ flip replicate) count where count = assocs . accumArray (+) 0 (lo, hi) . map (\i -> (i, 1)) $ l ``` ## Io {{trans|Java}} ```io List do( countingSort := method(min, max, count := list() setSize(max - min + 1) mapInPlace(0) foreach(x, count atPut(x - min, count at(x - min) + 1) ) j := 0 for(i, min, max, while(count at(i - min) > 0, atPut(j, i) count atPut(i - min, at(i - min) - 1) j = j + 1 ) ) self) countingSortInPlace := method( countingSort(min, max) ) ) l := list(2, 3, -4, 5, 1) l countingSortInPlace println # ==> list(-4, 1, 2, 3, 5) ``` A more functional-like version: ```io List do( fill := method(x, size, /* Resizes list to a given size and fills it with a given value. */ setSize(size) mapInPlace(x) ) countingSort := method(min, max, count := list() fill(0, max - min + 1) foreach(x, count atPut(x - min, count at(x - min) + 1) ) return count map(i, x, list() fill(i + min, x)) \ prepend(list()) reduce(xs, x, xs appendSeq(x)) ) countingSortInPlace := method( copy(countingSort(min, max)) ) ) l := list(2, 3, -4, 5, 1) l countingSortInPlace println # ==> list(-4, 1, 2, 3, 5) ``` =={{header|Icon}} and {{header|Unicon}}== The following example is hopefully in the spirit of a counting sort using a hash table as a substituted for a sparse array. Simply translating the pseudo-code would be very un-Iconish (as opposed to Uniconish). ```Icon procedure main() #: demonstrate various ways to sort a list and string write("Sorting Demo using ",image(countingsort)) writes(" on list : ") writex(UL) displaysort(countingsort,copy(UL)) end procedure countingsort(X) #: return sorted list (integers only) local T,lower,upper T := table(0) # hash table as sparse array lower := upper := X[1] every x := !X do { if not ( integer(x) = x ) then runerr(x,101) # must be integer lower >:= x # minimum upper <:= x # maximum T[x] +:= 1 # record x's and duplicates } every put(X := [],( 1 to T[i := lower to upper], i) ) # reconstitute with correct order and count return X end ``` Note: This example relies on [[Sorting_algorithms/Bubble_sort#Icon| the supporting procedures 'display sort', and 'writex' from Bubble Sort]]. Sample output: ```txt Sorting Demo using procedure countingsort on list : [ 3 14 1 5 9 2 6 3 ] with op = &null: [ 1 2 3 3 5 6 9 14 ] (0 ms) ``` =={{header|IS-BASIC}}==100 PROGRAM "CountSrt.bas" 110 RANDOMIZE 120 NUMERIC ARRAY(5 TO 24) 130 CALL INIT(ARRAY) 140 CALL WRITE(ARRAY) 150 CALL COUNTINGSORT(ARRAY) 160 CALL WRITE(ARRAY) 170 DEF INIT(REF A) 180 FOR I=LBOUND(A) TO UBOUND(A) 190 LET A(I)=RND(98)+1 200 NEXT 210 END DEF 220 DEF WRITE(REF A) 230 FOR I=LBOUND(A) TO UBOUND(A) 240 PRINT A(I); 250 NEXT 260 PRINT 270 END DEF 280 DEF FMIN(REF A) 290 LET T=INF 300 FOR I=LBOUND(A) TO UBOUND(A) 310 LET T=MIN(A(I),T) 320 NEXT 330 LET FMIN=T 340 END DEF 350 DEF FMAX(REF A) 360 LET T=-INF 370 FOR I=LBOUND(A) TO UBOUND(A) 380 LET T=MAX(A(I),T) 390 NEXT 400 LET FMAX=T 410 END DEF 420 DEF COUNTINGSORT(REF A) 430 LET MX=FMAX(A):LET MN=FMIN(A):LET Z=LBOUND(A) 440 NUMERIC COUNT(0 TO MX-MN) 450 FOR I=0 TO UBOUND(COUNT) 460 LET COUNT(I)=0 470 NEXT 480 FOR I=Z TO UBOUND(A) 490 LET COUNT(A(I)-MN)=COUNT(A(I)-MN)+1 500 NEXT 510 FOR I=MN TO MX 520 DO WHILE COUNT(I-MN)>0 530 LET A(Z)=I:LET Z=Z+1:LET COUNT(I-MN)=COUNT(I-MN)-1 540 LOOP 550 NEXT 560 END DEF ``` ## J {{eff note|J|/:~}} ```j csort =: monad define min =. <./y cnt =. 0 $~ 1+(>./y)-min for_a. y do. cnt =. cnt >:@{`[`]}~ a-min end. cnt # min+i.#cnt ) ``` Alternative implementation: ```j csort=: (+/@(=/) # ]) >./ (] + 1 i.@+ -) <./ ``` '''Example:''' ```j ] a =. _3 + 20 ?@$ 10 _2 _2 6 _1 1 6 _1 4 4 1 4 4 5 _3 5 3 0 _1 3 4 csort a _3 _2 _2 _1 _1 _1 0 1 1 3 3 4 4 4 4 4 5 5 6 6 ``` And note that this can be further simplified if the range is known in advance (which could easily be the case -- this sorting mechanism is practical when we have a small fixed range of values that we are sorting). Here, we do not need to inspect the data to find min and max values, since they are already known: ```j csrt=:2 :0 (m+i.n-m) (+/@(=/)~ # [) ] ) ``` or ```j csrt=:2 :0 (+/@(=/) # ])&(m+i.n-m) ) ``` Example: ```j (_3 csrt 17) a _3 _2 _2 _1 _1 _1 0 1 1 3 3 4 4 4 4 4 5 5 6 6 ``` ## Java {{works with|Java|1.5+}} ```java5 public static void countingSort(int[] array, int min, int max){ int[] count= new int[max - min + 1]; for(int number : array){ count[number - min]++; } int z= 0; for(int i= min;i <= max;i++){ while(count[i - min] > 0){ array[z]= i; z++; count[i - min]--; } } } ``` ## JavaScript ```javascript var countSort = function(arr, min, max) { var i, z = 0, count = []; for (i = min; i <= max; i++) { count[i] = 0; } for (i=0; i < arr.length; i++) { count[arr[i]]++; } for (i = min; i <= max; i++) { while (count[i]-- > 0) { arr[z++] = i; } } } ``` Testing: ```javascript // Line breaks are in HTML var i, ages = []; for (i = 0; i < 100; i++) { ages.push(Math.floor(Math.random() * (141))); } countSort(ages, 0, 140); for (i = 0; i < 100; i++) { document.write(ages[i] + "
"); } ``` ## jq {{works with | jq|1.4}} The task description points out the disadvantage of using an array to hold the counts, so in the following implementation, a JSON object is used instead. This ensures the space requirement is just O(length). In jq, this approach is both time and space efficient, except for the small cost of converting integers to strings, which is necessary because JSON keys must be strings. ```jq def countingSort(min; max): . as $in | reduce range(0;length) as $i ( {}; ($in[$i]|tostring) as $s | .[$s] += 1 # courtesy of the fact that in jq, (null+1) is 1 ) | . as $hash # now construct the answer: | reduce range(min; max+1) as $i ( []; ($i|tostring) as $s | if $hash[$s] == null then . else reduce range(0; $hash[$s]) as $j (.; . + [$i]) end ); ``` '''Example''': ```jq [1,2,1,4,0,10] | countingSort(0;10) ``` {{out}} ```sh $ jq -M -c -n -f counting_sort.jq [0,1,1,2,4,10] ``` ## Julia {{works with|Julia|0.6}} This is a translation of the pseudocode presented in the task description, accounting for the fact that Julia arrays start indexing at 1 rather than zero and taking care to return a result of the same type as the input. Note thatcnt
has the machine's standard integer type (typicallyInt64
), which need not match that of the input. ```julia function countsort(a::Vector{<:Integer}) lo, hi = extrema(a) b = zeros(a) cnt = zeros(eltype(a), hi - lo + 1) for i in a cnt[i-lo+1] += 1 end z = 1 for i in lo:hi while cnt[i-lo+1] > 0 b[z] = i z += 1 cnt[i-lo+1] -= 1 end end return b end v = rand(UInt8, 20) println("# unsorted bytes: $v\n -> sorted bytes: $(countsort(v))") v = rand(1:2 ^ 10, 20) println("# unsorted integers: $v\n -> sorted integers: $(countsort(v))") ``` {{out}} ```txt # unsorted bytes: UInt8[0xcc, 0x67, 0x64, 0xbd, 0x74, 0x18, 0xd2, 0xf8, 0xf1, 0x6c, 0x3e, 0x7c, 0x90, 0x07, 0x48, 0x99, 0xb3, 0xf8, 0x8f, 0x23] -> sorted bytes: UInt8[0x07, 0x18, 0x23, 0x3e, 0x48, 0x64, 0x67, 0x6c, 0x74, 0x7c, 0x8f, 0x90, 0x99, 0xb3, 0xbd, 0xcc, 0xd2, 0xf1, 0xf8, 0xf8] # unsorted integers: [634, 332, 756, 206, 971, 496, 962, 994, 795, 411, 981, 69, 366, 136, 227, 442, 731, 245, 179, 33] -> sorted integers: [33, 69, 136, 179, 206, 227, 245, 332, 366, 411, 442, 496, 634, 731, 756, 795, 962, 971, 981, 994] ``` ## Kotlin ```scala // version 1.1.0 fun countingSort(array: IntArray) { if (array.isEmpty()) return val min = array.min()!! val max = array.max()!! val count = IntArray(max - min + 1) // all elements zero by default for (number in array) count[number - min]++ var z = 0 for (i in min..max) while (count[i - min] > 0) { array[z++] = i count[i - min]-- } } fun main(args: Array) { val array = intArrayOf(4, 65, 2, -31, 0, 99, 2, 83, 782, 1) println("Original : ${array.asList()}") countingSort(array) println("Sorted : ${array.asList()}") } ``` {{out}} ```txt Original : [4, 65, 2, -31, 0, 99, 2, 83, 782, 1] Sorted : [-31, 0, 1, 2, 2, 4, 65, 83, 99, 782] ``` ## Langur ```Langur val .countingSort = f(.array) { val (.min, .max) = (min(.array), max(.array)) var .count = arr(.max-.min+1, 0) for .i in .array { .count[.i-.min+1] += 1 } var .result = [] for .i of .count { for of .count[.i] { .result ~= [.i+.min-1] } } return .result } val .data = [7, 234, -234, 9, 43, 123, 14] writeln "Original: ", .data writeln "Sorted : ", .countingSort(.data) ``` {{out}} ```txt Original: [7, 234, -234, 9, 43, 123, 14] Sorted : [-234, 7, 9, 14, 43, 123, 234] ``` ## Lua ```lua function CountingSort( f ) local min, max = math.min( unpack(f) ), math.max( unpack(f) ) local count = {} for i = min, max do count[i] = 0 end for i = 1, #f do count[ f[i] ] = count[ f[i] ] + 1 end local z = 1 for i = min, max do while count[i] > 0 do f[z] = i z = z + 1 count[i] = count[i] - 1 end end end f = { 15, -3, 0, -1, 5, 4, 5, 20, -8 } CountingSort( f ) for i in next, f do print( f[i] ) end ``` ## M4 ```M4 divert(-1) define(`randSeed',141592653) define(`setRand', `define(`randSeed',ifelse(eval($1<10000),1,`eval(20000-$1)',`$1'))') define(`rand_t',`eval(randSeed^(randSeed>>13))') define(`random', `define(`randSeed',eval((rand_t^(rand_t<<18))&0x7fffffff))randSeed') define(`set',`define(`$1[$2]',`$3')') define(`get',`defn(`$1[$2]')') define(`new',`set($1,size,0)') define(`append', `set($1,size,incr(get($1,size)))`'set($1,get($1,size),$2)') define(`deck', `new($1)for(`x',1,$2, `append(`$1',eval(random%$3))')') define(`for', `ifelse($#,0,``$0'', `ifelse(eval($2<=$3),1, `pushdef(`$1',$2)$4`'popdef(`$1')$0(`$1',incr($2),$3,`$4')')')') define(`show', `for(`x',1,get($1,size),`get($1,x) ')') define(`countingsort', `for(`x',$2,$3,`set(count,x,0)')`'for(`x',1,get($1,size), `set(count,get($1,x),incr(get(count,get($1,x))))')`'define(`z', 1)`'for(`x',$2,$3, `for(`y',1,get(count,x), `set($1,z,x)`'define(`z',incr(z))')')') divert deck(`a',10,100) show(`a') countingsort(`a',0,99) show(`a') ``` ## Mathematica ```Mathematica countingSort[list_] := Module[{minElem, maxElem, count, z, number}, minElem = Min[list]; maxElem = Max[list]; count = ConstantArray[0, (maxElem - minElem + 1)]; For[number = 1, number < Length[list], number++, count[[number - minElem + 1]] = count[[number - minElem + 1]] + 1;] ; z = 1; For[i = minElem, i < maxElem, i++, While[count[[i - minElem + 1]] > 0, list[[z]] = i; z++; count[[i - minElem + 1]] = count[[i - minElem + 1]] - 1;] ]; ] ``` ```txt countingSort@{2, 3, 1, 5, 7, 6} ->{1, 2, 3, 5, 6, 7} ``` =={{header|MATLAB}} / {{header|Octave}}== This is a direct translation of the pseudo-code, except to compensate for MATLAB using 1 based arrays. ```MATLAB function list = countingSort(list) minElem = min(list); maxElem = max(list); count = zeros((maxElem-minElem+1),1); for number = list count(number - minElem + 1) = count(number - minElem + 1) + 1; end z = 1; for i = (minElem:maxElem) while( count(i-minElem +1) > 0) list(z) = i; z = z+1; count(i - minElem + 1) = count(i - minElem + 1) - 1; end end end %countingSort ``` Sample Usage: ```MATLAB>> countingSort([4 3 1 5 6 2]) ans = 1 2 3 4 5 6 ``` ## MAXScript ```MAXScript fn countingSort arr = ( if arr.count < 2 do return arr local minVal = amin arr local maxVal = amax arr local count = for i in 1 to (maxVal-minVal+1) collect 0 for i in arr do ( count[i-minVal+1] = count[i-minVal+1] + 1 ) local z = 1 for i = minVal to maxVal do ( while (count[i-minVal+1]>0) do ( arr[z] = i z += 1 count[i-minVal+1] = count[i-minVal+1] - 1 ) ) return arr ) ``` {{out}} ```MAXScript a = for i in 1 to 15 collect random 1 30 #(7, 1, 6, 16, 27, 11, 24, 16, 25, 11, 22, 7, 28, 15, 17) countingSort a #(1, 6, 7, 7, 11, 11, 15, 16, 16, 17, 22, 24, 25, 27, 28) ``` =={{header|Modula-3}}== ```modula3 MODULE Counting EXPORTS Main; IMPORT IO, Fmt; VAR test := ARRAY [1..8] OF INTEGER {80, 10, 40, 60, 50, 30, 20, 70}; PROCEDURE Sort(VAR a: ARRAY OF INTEGER; min, max: INTEGER) = VAR range := max - min + 1; count := NEW(REF ARRAY OF INTEGER, range); z := 0; BEGIN FOR i := FIRST(count^) TO LAST(count^) DO count[i] := 0; END; FOR i := FIRST(a) TO LAST(a) DO INC(count[a[i] - min]); END; FOR i := min TO max DO WHILE (count[i - min] > 0) DO a[z] := i; INC(z); DEC(count[i - min]); END; END; END Sort; BEGIN IO.Put("Unsorted: "); FOR i := FIRST(test) TO LAST(test) DO IO.Put(Fmt.Int(test[i]) & " "); END; IO.Put("\n"); Sort(test, 10, 80); IO.Put("Sorted: "); FOR i := FIRST(test) TO LAST(test) DO IO.Put(Fmt.Int(test[i]) & " "); END; IO.Put("\n"); END Counting. ``` Output: ```txt Unsorted: 80 10 40 60 50 30 20 70 Sorted: 10 20 30 40 50 60 70 80 ``` ## NetRexx ### Version 1 An almost direct implementation of the pseudocode. ```NetRexx /* NetRexx */ options replace format comments java crossref savelog symbols binary import java.util.List icounts = [int - 1, 3, 6, 2, 7, 13, 20, 12, 21, 11 - , 22, 10, 23, 9, 24, 8, 25, 43, 62, 42 - , 63, 41, 18, 42, 17, 43, 16, 44, 15, 45 - , 14, 46, 79, 113, 78, 114, 77, 39, 78, 38 - ] scounts = int[icounts.length] System.arraycopy(icounts, 0, scounts, 0, icounts.length) lists = [ - icounts - , countingSort(scounts) - ] loop ln = 0 to lists.length - 1 cl = lists[ln] rep = Rexx('') loop ct = 0 to cl.length - 1 rep = rep cl[ct] end ct say '['rep.strip.changestr(' ', ',')']' end ln return method getMin(array = int[]) public constant binary returns int amin = Integer.MAX_VALUE loop x_ = 0 to array.length - 1 if array[x_] < amin then amin = array[x_] end x_ return amin method getMax(array = int[]) public constant binary returns int amax = Integer.MIN_VALUE loop x_ = 0 to array.length - 1 if array[x_] > amax then amax = array[x_] end x_ return amax method countingSort(array = int[], amin = getMin(array), amax = getMax(array)) public constant binary returns int[] count = int[amax - amin + 1] loop nr = 0 to array.length - 1 numbr = array[nr] count[numbr - amin] = count[numbr - amin] + 1 end nr z_ = 0 loop i_ = amin to amax loop label count while count[i_ - amin] > 0 array[z_] = i_ z_ = z_ + 1 count[i_ - amin] = count[i_ - amin] - 1 end count end i_ return array ``` {{out}} [1,3,6,2,7,13,20,12,21,11,22,10,23,9,24,8,25,43,62,42,63,41,18,42,17,43,16,44,15,45,14,46,79,113,78,114,77,39,78,38] [1,2,3,6,7,8,9,10,11,12,13,14,15,16,17,18,20,21,22,23,24,25,38,39,41,42,42,43,43,44,45,46,62,63,77,78,78,79,113,114] ``` ### Version 2 A more Rexx-like (and shorter) version. Due to NetRexx's built in indexed string capability, negative values are also easily supported. ```NetRexx /* NetRexx */ options replace format comments java crossref symbols nobinary runSample(arg) return -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method countingSort(icounts) public constant parse getMinMax(icounts) amin amax array = 0 loop ix = 1 to icounts.words iw = icounts.word(ix) + 0 array[iw] = array[iw] + 1 end ix ocounts = '' loop ix = amin to amax if array[ix] = 0 then iterate ix loop for array[ix] ocounts = ocounts ix end end ix return ocounts.space -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method getMinMax(icounts) public constant amin = Long.MAX_VALUE amax = Long.MIN_VALUE loop x_ = 1 to icounts.words amin = icounts.word(x_).min(amin) amax = icounts.word(x_).max(amax) end x_ return amin amax -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method runSample(arg) public static parse arg icounts if icounts = '' then - icounts = - ' 1 3 6 2 7 13 20 12 21 11 22 10 23 9 24 8 25 43 62 42' - '63 41 18 42 17 43 16 44 15 45 14 46 79 113 78 114 77 39 78 38' - '0 -200 -6 -10 -0' - '' say icounts.space say countingSort(icounts) return ``` {{out}} ```txt 1 3 6 2 7 13 20 12 21 11 22 10 23 9 24 8 25 43 62 42 63 41 18 42 17 43 16 44 15 45 14 46 79 113 78 114 77 39 78 38 0 -200 -6 -10 -0 -200 -10 -6 0 0 1 2 3 6 7 8 9 10 11 12 13 14 15 16 17 18 20 21 22 23 24 25 38 39 41 42 42 43 43 44 45 46 62 63 77 78 78 79 113 114 ``` ## Nim ```nim proc countingSort[T](a: var openarray[T]; min, max: int) = let range = max - min + 1 var count = newSeq[T](range) var z = 0 for i in 0 .. < a.len: inc count[a[i] - min] for i in min .. max: for j in 0 ..PrintLine(); }; } function : CountingSort(array : Int[], min : Int, max : Int) ~ Nil { count := Int->New[max - min + 1]; each(i : array) { number := array[i]; v := count[number - min]; count[number - min] := v + 1; }; z := 0; for(i := min; i <= max; i += 1;) { while(count[i - min] > 0) { array[z] := i; z += 1; v := count[i - min] count[i - min] := v - 1; }; }; } } } ``` ## OCaml For arrays: ```ocaml let counting_sort_array arr lo hi = let count = Array.make (hi-lo+1) 0 in Array.iter (fun i -> count.(i-lo) <- count.(i-lo) + 1) arr; Array.concat (Array.to_list (Array.mapi (fun i x -> Array.make x (lo+i)) count)) ``` ## Octave This implements the same algorithm but in a more compact way (using the same loop to count and to ''update'' the sorted vector). This implementation is ''elegant'' (and possible since the sort is not done "in place"), but not so efficient on machines that can't parallelize some operations (the vector arr is scanned for every value between minval and maxval) ```octave function r = counting_sort(arr, minval, maxval) r = arr; z = 1; for i = minval:maxval cnt = sum(arr == i); while( cnt-- > 0 ) r(z++) = i; endwhile endfor endfunction ``` Testing: ```octave ages = unidrnd(140, 100, 1); sorted = counting_sort(ages, 0, 140); disp(sorted); ``` ## Oz Using arrays as in the original algorithm. The implementation is slightly simpler because arrays can start with an arbitrary index in Oz. ```oz declare proc {CountingSort Arr Min Max} Count = {Array.new Min Max 0} Z = {NewCell {Array.low Arr}} in %% fill frequency array for J in {Array.low Arr}..{Array.high Arr} do Number = Arr.J in Count.Number := Count.Number + 1 end %% recreate array from frequencies for I in Min..Max do for C in 1..Count.I do Arr.(@Z) := I Z := @Z + 1 end end end A = {Tuple.toArray unit(3 1 4 1 5 9 2 6 5)} in {CountingSort A 1 9} {Show {Array.toRecord unit A}} ``` Using lists for input and output and a dictionary as a sparse array: ```oz declare fun {CountingSort Xs} Count = {Dictionary.new} in for X in Xs do Count.X := {CondSelect Count X 0} + 1 end {Concat {Map {Dictionary.entries Count} Repeat}} end fun {Repeat Val#Count} if Count == 0 then nil else Val|{Repeat Val#Count-1} end end fun {Concat Xs} {FoldR Xs Append nil} end in {Show {CountingSort [3 1 4 1 5 9 2 6 5]}} ``` ## PARI/GP ```parigp countingSort(v,mn,mx)={ my(u=vector(#v),i=0); for(n=mn,mx, for(j=1,#v,if(v[j]==n,u[i++]=n)) ); u }; ``` ## Pascal ```pascal program CountingSort; procedure counting_sort(var arr : Array of Integer; n, min, max : Integer); var count : Array of Integer; i, j, z : Integer; begin SetLength(count, max-min); for i := 0 to (max-min) do count[i] := 0; for i := 0 to (n-1) do count[ arr[i] - min ] := count[ arr[i] - min ] + 1; z := 0; for i := min to max do for j := 0 to (count[i - min] - 1) do begin arr[z] := i; z := z + 1 end end; var ages : Array[0..99] of Integer; i : Integer; begin { testing } for i := 0 to 99 do ages[i] := 139 - i; counting_sort(ages, 100, 0, 140); for i := 0 to 99 do writeln(ages[i]); end. ``` ## Perl ```perl #! /usr/bin/perl use strict; sub counting_sort { my ($a, $min, $max) = @_; my @cnt = (0) x ($max - $min + 1); $cnt[$_ - $min]++ foreach @$a; my $i = $min; @$a = map {($i++) x $_} @cnt; } ``` Testing: ```perl my @ages = map {int(rand(140))} 1 .. 100; counting_sort(\@ages, 0, 140); print join("\n", @ages), "\n"; ``` ## Perl 6 {{Works with|rakudo|2018.03}} ```perl6 sub counting-sort (@ints) { my $off = @ints.min; (my @counts)[$_ - $off]++ for @ints; flat @counts.kv.map: { ($^k + $off) xx ($^v // 0) } } # Testing: constant @age-range = 2 .. 102; my @ages = @age-range.roll(50); say @ages.&counting-sort; say @ages.sort; say @ages.&counting-sort.join eq @ages.sort.join ?? 'ok' !! 'not ok'; ``` {{out}} ```txt (5 5 5 7 9 17 19 19 20 21 25 27 28 30 32 34 38 40 41 45 48 49 50 51 53 54 55 56 59 62 65 66 67 69 70 73 74 81 83 85 87 91 91 93 94 96 99 99 100 101) (5 5 5 7 9 17 19 19 20 21 25 27 28 30 32 34 38 40 41 45 48 49 50 51 53 54 55 56 59 62 65 66 67 69 70 73 74 81 83 85 87 91 91 93 94 96 99 99 100 101) ok ``` ## Phix ```Phix function countingSort(sequence array, integer mina, maxa) sequence count = repeat(0,maxa-mina+1) for i=1 to length(array) do count[array[i]-mina+1] += 1 end for integer z = 1 for i=mina to maxa do for j=1 to count[i-mina+1] do array[z] := i z += 1 end for end for return array end function sequence s = {5, 3, 1, 7, 4, 1, 1, 20} ?countingSort(s,min(s),max(s)) ``` {{out}} ```txt {1,1,1,3,4,5,7,20} ``` ## PHP ```php 0 ) { $arr[$z++] = $i; } } } ``` Testing: ```php $ages = array(); for($i=0; $i < 100; $i++) { array_push($ages, rand(0, 140)); } counting_sort($ages, 0, 140); for($i=0; $i < 100; $i++) { echo $ages[$i] . "\n"; } ?> ``` ## PicoLisp ```PicoLisp (de countingSort (Lst Min Max) (let Count (need (- Max Min -1) 0) (for N Lst (inc (nth Count (- N Min -1))) ) (make (map '((C I) (do (car C) (link (car I))) ) Count (range Min Max) ) ) ) ) ``` Output: ```txt : (countingSort (5 3 1 7 4 1 1 20) 1 20) -> (1 1 1 3 4 5 7 20) ``` ## PL/I ```PL/I count_sort: procedure (A); declare A(*) fixed; declare (min, max) fixed; declare i fixed binary; max, min = A(lbound(A,1)); do i = 1 to hbound(A,1); if max < A(i) then max = A(i); if min > A(i) then min = A(i); end; begin; declare t(min:max) fixed; declare (i, j, k) fixed binary (31); t = 0; do i = 1 to hbound(A,1); j = A(i); t(j) = t(j) + 1; end; k = lbound(A,1); do i = min to max; if t(i) ^= 0 then do j = 1 to t(i); A(k) = i; k = k + 1; end; end; end; end count_sort; ``` ## PowerShell ```PowerShell function countingSort($array) { $minmax = $array | Measure-Object -Minimum -Maximum $min, $max = $minmax.Minimum, $minmax.Maximum $count = @(0) * ($max - $min + 1) foreach ($number in $array) { $count[$number - $min] = $count[$number - $min] + 1 } $z = 0 foreach ($i in $min..$max) { while (0 -lt $count[$i - $min]) { $array[$z] = $i $z = $z+1 $count[$i - $min] = $count[$i - $min] - 1 } } $array } $array = foreach ($i in 1..50) {Get-Random -Minimum 0 -Maximum 26} "$array" "$(countingSort $array)" ``` Output: ```txt 13 18 8 6 3 7 22 20 10 7 18 10 25 13 9 21 8 19 24 24 18 6 23 23 24 7 15 25 24 25 11 23 19 5 4 8 9 7 1 19 10 24 13 1 9 0 9 10 19 16 0 1 1 3 4 5 6 6 7 7 7 7 8 8 8 9 9 9 9 10 10 10 10 11 13 13 13 15 16 18 18 18 19 19 19 19 20 21 22 23 23 23 24 24 24 24 24 25 25 25 ``` ## PureBasic ```PureBasic Procedure Counting_sort(Array data_array(1), min, max) Define i, j Dim c(max - min) For i = 0 To ArraySize(data_array()) c(data_array(i) - min) + 1 Next For i = 0 To ArraySize(c()) While c(i) data_array(j) = i + min j + 1 c(i) - 1 Wend Next EndProcedure ``` ## Python Follows the spirit of the counting sort but uses Pythons defaultdict(int) to initialize array accesses to zero, and list concatenation: ```python>>> from collections import defaultdict >>> def countingSort(array, mn, mx): count = defaultdict(int) for i in array: count[i] += 1 result = [] for j in range(mn,mx+1): result += [j]* count[j] return result >>> data = [9, 7, 10, 2, 9, 7, 4, 3, 10, 2, 7, 10, 2, 1, 3, 8, 7, 3, 9, 5, 8, 5, 1, 6, 3, 7, 5, 4, 6, 9, 9, 6, 6, 10, 2, 4, 5, 2, 8, 2, 2, 5, 2, 9, 3, 3, 5, 7, 8, 4] >>> mini,maxi = 1,10 >>> countingSort(data, mini, maxi) == sorted(data) True ``` Using a list: {{works with|Python|2.6}} ```python def countingSort(a, min, max): cnt = [0] * (max - min + 1) for x in a: cnt[x - min] += 1 return [x for x, n in enumerate(cnt, start=min) for i in xrange(n)] ``` ## R {{trans|Octave}} ```R counting_sort <- function(arr, minval, maxval) { r <- arr z <- 1 for(i in minval:maxval) { cnt = sum(arr == i) while(cnt > 0) { r[z] = i z <- z + 1 cnt <- cnt - 1 } } r } # 140+1 instead of 140, since random numbers generated # by runif are always less than the given maximum; # floor(a number at most 140.9999...) is 140 ages <- floor(runif(100, 0, 140+1)) sorted <- counting_sort(ages, 0, 140) print(sorted) ``` ## Racket ```racket #lang racket (define (counting-sort xs min max) (define ns (make-vector (+ max (- min) 1) 0)) (for ([x xs]) (vector-set! ns (- x min) (+ (vector-ref ns (- x min)) 1))) (for/fold ([i 0]) ([n ns] [x (in-naturals)]) (for ([j (in-range i (+ i n ))]) (vector-set! xs j (+ x min))) (+ i n)) xs) (counting-sort (vector 0 9 3 8 1 -1 1 2 3 7 4) -1 10) ``` Output: ```racket '#(-1 0 1 1 2 3 3 4 7 8 9) ``` ## REXX These REXX versions make use of ''sparse'' arrays. Negative, zero, and positive integers are supported. ### version 1 ```rexx /*REXX pgm sorts an array of integers (can be negative) using the count─sort algorithm.*/ $=1 3 6 2 7 13 20 12 21 11 22 10 23 9 24 8 25 43 62 42 63 41 18 42 17 43 16 44 15 45 14 46 79 113 78 114 77 39 78 38 #= words($); w= length(#); _.= 0 /* [↑] a list of some Recaman numbers.*/ m= 0; LO= word($, 1); HI= LO /*M: max width of any number in @. */ do i=1 for #; z= word($, i); @.i= z; m= max(m, length(z)) /*get from $ list. */ _.z= _.z + 1; LO= min(LO, z); HI= max(HI, z) /*find the LO & HI.*/ end /*i*/ /*W: max index width for the @. array*/ call show 'before sort: ' /*show the before array elements. */ say copies('▒', 55) /*show a separator line (before/after).*/ call countSort # /*sort a number of entries of @. array.*/ call show ' after sort: ' /*show the after array elements. */ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ countSort: parse arg N; x= 1; do k=LO to HI; do x=x for _.k; @.x= k; end /*x*/ end /*k*/ return /*──────────────────────────────────────────────────────────────────────────────────────*/ show: do s=1 for #; say right("element",20) right(s,w) arg(1) right(@.s,m); end; return ``` {{out|output|text= when using the default input:}} (Shown at '''5/6''' size.) element 1 before sort: 1 element 2 before sort: 3 element 3 before sort: 6 element 4 before sort: 2 element 5 before sort: 7 element 6 before sort: 13 element 7 before sort: 20 element 8 before sort: 12 element 9 before sort: 21 element 10 before sort: 11 element 11 before sort: 22 element 12 before sort: 10 element 13 before sort: 23 element 14 before sort: 9 element 15 before sort: 24 element 16 before sort: 8 element 17 before sort: 25 element 18 before sort: 43 element 19 before sort: 62 element 20 before sort: 42 element 21 before sort: 63 element 22 before sort: 41 element 23 before sort: 18 element 24 before sort: 42 element 25 before sort: 17 element 26 before sort: 43 element 27 before sort: 16 element 28 before sort: 44 element 29 before sort: 15 element 30 before sort: 45 element 31 before sort: 14 element 32 before sort: 46 element 33 before sort: 79 element 34 before sort: 113 element 35 before sort: 78 element 36 before sort: 114 element 37 before sort: 77 element 38 before sort: 39 element 39 before sort: 78 element 40 before sort: 38 ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ element 1 after sort: 1 element 2 after sort: 2 element 3 after sort: 3 element 4 after sort: 6 element 5 after sort: 7 element 6 after sort: 8 element 7 after sort: 9 element 8 after sort: 10 element 9 after sort: 11 element 10 after sort: 12 element 11 after sort: 13 element 12 after sort: 14 element 13 after sort: 15 element 14 after sort: 16 element 15 after sort: 17 element 16 after sort: 18 element 17 after sort: 20 element 18 after sort: 21 element 19 after sort: 22 element 20 after sort: 23 element 21 after sort: 24 element 22 after sort: 25 element 23 after sort: 38 element 24 after sort: 39 element 25 after sort: 41 element 26 after sort: 42 element 27 after sort: 42 element 28 after sort: 43 element 29 after sort: 43 element 30 after sort: 44 element 31 after sort: 45 element 32 after sort: 46 element 33 after sort: 62 element 34 after sort: 63 element 35 after sort: 77 element 36 after sort: 78 element 37 after sort: 78 element 38 after sort: 79 element 39 after sort: 113 element 40 after sort: 114 ``` ### version 2 {{trans|PL/I}} ```rexx /* REXX --------------------------------------------------------------- * 13.07.2014 Walter Pachl translated from PL/I *--------------------------------------------------------------------*/ alist='999 888 777 1 5 13 15 17 19 21 5' Parse Var alist lo hi . Do i=1 By 1 While alist<>'' Parse Var alist a.i alist; lo=min(lo,a.i) hi=max(hi,a.i) End a.0=i-1 Call show 'before count_sort' Call count_sort Call show 'after count_sort' Exit count_sort: procedure Expose a. lo hi t.=0 do i=1 to a.0 j=a.i t.j=t.j+1 end k=1 do i=lo to hi if t.i<>0 then Do do j=1 to t.i a.k=i k=k+1 end end end Return show: Procedure Expose a. Parse Arg head Say head ol='' Do i=1 To a.0 ol=ol right(a.i,3) End Say ol Return ``` '''Output:''' ```txt before count_sort 999 888 777 1 5 13 15 17 19 21 5 after count_sort 1 5 5 13 15 17 19 21 777 888 999 ``` ## Ring ```ring aList = [4, 65, 2, 99, 83, 782, 1] see countingSort(aList, 1, 782) func countingSort f, min, max count = list(max-min+1) for i = min to max count[i] = 0 next for i = 1 to len(f) count[ f[i] ] = count[ f[i] ] + 1 next z = 1 for i = min to max while count[i] > 0 f[z] = i z = z + 1 count[i] = count[i] - 1 end next return f ``` ## Ruby ```ruby class Array def counting_sort! replace counting_sort end def counting_sort min, max = minmax count = Array.new(max - min + 1, 0) each {|number| count[number - min] += 1} (min..max).each_with_object([]) {|i, ary| ary.concat([i] * count[i - min])} end end ary = [9,7,10,2,9,7,4,3,10,2,7,10,2,1,3,8,7,3,9,5,8,5,1,6,3,7,5,4,6,9,9,6,6,10,2,4,5,2,8,2,2,5,2,9,3,3,5,7,8,4] p ary.counting_sort.join(",") # => "1,1,2,2,2,2,2,2,2,2,3,3,3,3,3,3,4,4,4,4,5,5,5,5,5,5,6,6,6,6,7,7,7,7,7,7,8,8,8,8,9,9,9,9,9,9,10,10,10,10" p ary = Array.new(20){rand(-10..10)} # => [-3, -1, 9, -6, -8, -3, 5, -7, 4, 0, 5, 0, 2, -2, -6, 10, -10, -7, 5, -7] p ary.counting_sort # => [-10, -8, -7, -7, -7, -6, -6, -3, -3, -2, -1, 0, 0, 2, 4, 5, 5, 5, 9, 10] ``` ## Rust ```rust fn counting_sort( mut data: Vec, min: usize, max: usize, ) -> Vec { // create and fill counting bucket with 0 let mut count: Vec = Vec::with_capacity(data.len()); count.resize(data.len(), 0); for num in &data { count[num - min] = count[num - min] + 1; } let mut z: usize = 0; for i in min..max+1 { while count[i - min] > 0 { data[z] = i; z += 1; count[i - min] = count[i - min] - 1; } } data } fn main() { let arr1 = vec![1, 0, 2, 9, 3, 8, 4, 7, 5, 6]; println!("{:?}", counting_sort(arr1, 0, 9)); let arr2 = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; println!("{:?}", counting_sort(arr2, 0, 9)); let arr3 = vec![10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]; println!("{:?}", counting_sort(arr3, 0, 10)); } ``` {{out}} ```txt [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] ``` ## Scala ```scala def countSort(input: List[Int], min: Int, max: Int): List[Int] = input.foldLeft(Array.fill(max - min + 1)(0)) { (arr, n) => arr(n - min) += 1 arr }.zipWithIndex.foldLeft(List[Int]()) { case (lst, (cnt, ndx)) => List.fill(cnt)(ndx + min) ::: lst }.reverse ``` It's better (i.e. slightly faster) to reverse the frequencies list before processing it, instead of the whole result ```scala def countSort(input: List[Int], min: Int, max: Int): List[Int] = input.foldLeft(Array.fill(max - min + 1)(0)) { (arr, n) => arr(n - min) += 1 arr }.zipWithIndex.reverse.foldLeft(List[Int]()) { case (lst, (cnt, ndx)) => List.fill(cnt)(ndx + min) ::: lst } ``` ## Sidef ```ruby func counting_sort(a, min, max) { var cnt = ([0] * (max - min + 1)) a.each {|i| cnt[i-min]++ } cnt.map {|i| [min++] * i }.flat } var a = 100.of { 100.irand } say counting_sort(a, 0, 100) ``` ## Slate ```slate s@(Sequence traits) countingSort &min: min &max: max [| counts index | min `defaultsTo: (s reduce: #min: `er). max `defaultsTo: (s reduce: #max: `er). counts: ((0 to: max - min) project: [| :_ | 0]). s do: [| :value | counts at: value - min infect: [| :count | count + 1]]. index: 0. min to: max do: [| :value | [(counts at: value - min) isPositive] whileTrue: [s at: index put: value. index: index + 1. counts at: value - min infect: [| :val | val - 1]] ]. s ]. ``` ## Smalltalk {{works with|GNU Smalltalk}} ```smalltalk OrderedCollection extend [ countingSortWithMin: min andMax: max [ |oc z| oc := OrderedCollection new. 1 to: (max - min + 1) do: [ :n| oc add: 0 ]. self do: [ :v | oc at: (v - min + 1) put: ( (oc at: (v - min + 1)) + 1) ]. z := 1. min to: max do: [ :i | 1 to: (oc at: (i - min + 1)) do: [ :k | self at: z put: i. z := z + 1. ] ] ] ]. ``` Testing: ```smalltalk |ages| ages := OrderedCollection new. 1 to: 100 do: [ :n | ages add: (Random between: 0 and: 140) ]. ages countingSortWithMin: 0 andMax: 140. ages printNl. ``` ## Tcl {{works with|Tcl|8.5}} ```tcl proc countingsort {a {min ""} {max ""}} { # If either of min or max weren't given, compute them now if {$min eq ""} { set min [::tcl::mathfunc::min $a] } if {$max eq ""} { set max [::tcl::mathfunc::max $a] } # Make the "array" of counters set count [lrepeat [expr {$max - $min + 1}] 0] # Count the values in the input list foreach n $a { set idx [expr {$n - $min}] lincr count $idx } # Build the output list set z 0 for {set i $min} {$i <= $max} {incr i} { set idx [expr {$i - $min}] while {[lindex $count $idx] > 0} { lset a $z $i incr z lincr count $idx -1 } } return $a } # Helper that will increment an existing element of a list proc lincr {listname idx {value 1}} { upvar 1 $listname list lset list $idx [expr {[lindex $list $idx] + $value}] } # Demo code for {set i 0} {$i < 50} {incr i} {lappend a [expr {1+ int(rand()*10)}]} puts $a puts [countingsort $a] ``` ```txt 9 7 10 2 9 7 4 3 10 2 7 10 2 1 3 8 7 3 9 5 8 5 1 6 3 7 5 4 6 9 9 6 6 10 2 4 5 2 8 2 2 5 2 9 3 3 5 7 8 4 1 1 2 2 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 5 5 5 5 5 5 6 6 6 6 7 7 7 7 7 7 8 8 8 8 9 9 9 9 9 9 10 10 10 10 ``` ## VBA {{trans|Phix}} ```vb Option Base 1 Private Function countingSort(array_ As Variant, mina As Long, maxa As Long) As Variant Dim count() As Integer ReDim count(maxa - mina + 1) For i = 1 To UBound(array_) count(array_(i) - mina + 1) = count(array_(i) - mina + 1) + 1 Next i Dim z As Integer: z = 1 For i = mina To maxa For j = 1 To count(i - mina + 1) array_(z) = i z = z + 1 Next j Next i countingSort = array_ End Function Public Sub main() s = [{5, 3, 1, 7, 4, 1, 1, 20}] Debug.Print Join(countingSort(s, WorksheetFunction.Min(s), WorksheetFunction.Max(s)), ", ") End Sub ``` {{out}} ```txt 1, 1, 1, 3, 4, 5, 7, 20 ``` ## VBScript All my other sort demos just pass in the array, thus the findMax and findMin ### ==Implementation== ```vb function findMax( a ) dim num dim max max = 0 for each num in a if num > max then max = num next findMax = max end function function findMin( a ) dim num dim min min = 0 for each num in a if num < min then min = num next findMin = min end function 'the function returns the sorted array, but the fact is that VBScript passes the array by reference anyway function countingSort( a ) dim count() dim min, max min = findMin(a) max = findMax(a) redim count( max - min + 1 ) dim i dim z for i = 0 to ubound( a ) count( a(i) - min ) = count( a( i ) - min ) + 1 next z = 0 for i = min to max while count( i - min) > 0 a(z) = i z = z + 1 count( i - min ) = count( i - min ) - 1 wend next countingSort = a end function ``` ### ==Invocation== ```vb dim a a = array(300, 1, -2, 3, -4, 5, -6, 7, -8, 100, 11 ) wscript.echo join( a, ", " ) countingSort a wscript.echo join( a, ", " ) ``` ### ==Output== ```txt 300, 1, -2, 3, -4, 5, -6, 7, -8, 100, 11 -8, -6, -4, -2, 1, 3, 5, 7, 11, 100, 300 ``` ## XPL0 ```XPL0 include c:\cxpl\codes; proc CountingSort(Array, Min, Max, Size); \Sort Array int Array, Min, Max, Size; \minimum, maximum values, number of elements int Count, I, Z; [Count:= Reserve((Max-Min+1)*4); \Reserve Count with 4 bytes per integer for I:= 0 to Max-Min do Count(I):= 0; \initialize Count with 0 for I:= 0 to Size-1 do \for each number count its occurrences Count(Array(I)-Min):= Count(Array(I)-Min) + 1; Z:= 0; for I:= Min to Max do while Count(I-Min) > 0 do [Array(Z):= I; Z:= Z+1; Count(I-Min):= Count(I-Min) - 1; ]; ]; int A, I; [A:= [3, 1, 4, 1, -5, 9, 2, 6, 5, 4]; CountingSort(A, -5, 9, 10); for I:= 0 to 10-1 do [IntOut(0, A(I)); ChOut(0, ^ )]; ] ``` {{out}} ```txt -5 1 1 2 3 4 4 5 6 9 ``` ## zkl ```zkl fcn countingSort(array, min, max){ // modifies array count:=(max - min + 1).pump(List().write,0); // array of (max - min + 1) zeros foreach number in (array){ count[number - min] += 1; } z:=-1; foreach i in ([min .. max]){ do(count[i - min]){ array[z += 1] = i } } array } ``` ```zkl array:=List(4, 65, 2, -31, 0, 99, 2, 83, 182, 1); countingSort(array,(0).min(array), (0).max(array)).println(); ``` {{out}} ```txt L(-31,0,1,2,2,4,65,83,99,182) ``` {{omit from|GUISS}}