Sorting algorithms/Radix sort
Sort an integer array with the radix sort algorithm.
You are encouraged to solve this task according to the task description, using any language you may know.
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
Heap sort | Merge sort | Patience sort | Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
- Task
The primary purpose is to complete the characterization of sort algorithms task.
Ada
radix_sort.adb: <lang Ada>with Ada.Text_IO; procedure Radix_Sort is
type Integer_Array is array (Positive range <>) of Integer;
procedure Least_Significant_Radix_Sort (Data : in out Integer_Array; Base : Positive := 10) is
type Bucket is record
Count : Natural := 0;
Content : Integer_Array (Data'Range);
end record;
subtype Bucket_Index is Integer range -Base + 1 .. Base - 1;
type Bucket_Array is array (Bucket_Index) of Bucket;
procedure Append (To : in out Bucket; Item : Integer) is
begin
To.Count := To.Count + 1;
To.Content (To.Count) := Item;
end Append;
function Get_Nth_Digit (Value : Integer; N : Positive) return Integer is
Result : Integer := (Value / (Base ** (N - 1))) mod Base;
begin
if Value < 0 then
Result := -Result;
end if;
return Result;
end Get_Nth_Digit;
function Get_Maximum return Natural is
Result : Natural := 0;
begin
for I in Data'Range loop
if abs (Data (I)) > Result then
Result := abs (Data (I));
end if;
end loop;
return Result;
end Get_Maximum;
function Split (Pass : Positive) return Bucket_Array is
Buckets : Bucket_Array;
begin
for I in Data'Range loop
Append (To => Buckets (Get_Nth_Digit (Data (I), Pass)),
Item => Data (I));
end loop;
return Buckets;
end Split;
function Merge (Buckets : Bucket_Array) return Integer_Array is
Result : Integer_Array (Data'Range);
Current_Index : Positive := 1;
begin
for Sublist in Buckets'Range loop
for Item in 1 .. Buckets (Sublist).Count loop
Result (Current_Index) := Buckets (Sublist).Content (Item);
Current_Index := Current_Index + 1;
end loop;
end loop;
return Result;
end Merge;
Max_Number : Natural := Get_Maximum;
Digit_Count : Positive := 1;
begin
-- count digits of biggest number
while Max_Number > Base loop
Digit_Count := Digit_Count + 1;
Max_Number := Max_Number / Base;
end loop;
for Pass in 1 .. Digit_Count loop
Data := Merge (Split (Pass));
end loop;
end Least_Significant_Radix_Sort;
Test_Array : Integer_Array := (170, 45, 75, -90, -802, 24, 2, 66);
begin
Least_Significant_Radix_Sort (Test_Array, 4);
for I in Test_Array'Range loop
Ada.Text_IO.Put (Integer'Image (Test_Array (I)));
end loop;
Ada.Text_IO.New_Line;
end Radix_Sort;</lang>
output:
-802-90 2 24 45 66 75 170
ALGOL 68
<lang algol68>PROC radixsort = (REF []INT array) VOID: (
[UPB array]INT zero;
[UPB array]INT one;
BITS mask := 16r01;
INT zero_index := 0,
one_index := 0,
array_index := 1;
WHILE ABS(mask) > 0 DO
WHILE array_index <= UPB array DO
IF (BIN(array[array_index]) AND mask) = 16r0 THEN
zero_index +:= 1;
zero[zero_index] := array[array_index]
ELSE
one_index +:= 1;
one[one_index] := array[array_index]
FI;
array_index +:= 1
OD;
array_index := 1;
FOR i FROM 1 TO zero_index DO
array[array_index] := zero[i];
array_index +:= 1
OD;
FOR i FROM 1 TO one_index DO
array[array_index] := one[i];
array_index +:=1
OD;
array_index := 1;
zero_index := one_index := 0;
mask := mask SHL 1
OD
);
main: (
[10]INT a;
FOR i FROM 1 TO UPB a DO
a[i] := ROUND(random*1000)
OD;
print(("Before:", a));
print((newline, newline));
radixsort(a);
print(("After: ", a))
)</lang>
- Output:
Before: +459 +941 +623 +386 +263 +766 +129 +554 +160 +328
After: +129 +160 +263 +328 +386 +459 +554 +623 +766 +941
AutoHotkey
<lang AutoHotkey>Radix_Sort(data){ loop, parse, data, `, n := StrLen(A_LoopField)>n?StrLen(A_LoopField):n loop % n { bucket := [] , i := A_Index loop, parse, data, `, bucket[SubStr(A_LoopField,1-i)] .= (bucket[SubStr(A_LoopField,1-i)]?",":"") A_LoopField data := "" for i, v in bucket data .= (data?",":"") v } return data }</lang> Examples:<lang AutoHotkey>d = 170,45,75,90,802,2,24,66 MsgBox, 262144, , % Radix_Sort(d)</lang>
Outputs:
2,24,45,66,75,90,170,802
B4X
<lang b4x>Sub RadixSort (Old() As Int) Dim i, j As Int Dim tmp(Old.Length) As Int For shift = 31 To 0 Step - 1 j = 0 For i = 0 To Old.Length - 1 Dim move As Boolean = Bit.ShiftLeft(Old(i), shift) >= 0 If (shift = 0 And move = False) Or (shift <> 0 And move) Then Old(i - j) = Old(i) Else tmp(j) = Old(i) j = j + 1 End If Next Bit.ArrayCopy(tmp, 0, Old, Old.Length - j, j) Next End Sub
Sub Test Dim arr() As Int = Array As Int(34, 23, 54, -123, 543, 123) RadixSort(arr) For Each i As Int In arr Log(i) Next End Sub</lang> Output:
-123 23 34 54 123 543
BBC BASIC
The array index is assumed to start at zero. The third parameter of PROCradixsort() is the radix used. <lang bbcbasic> DIM test%(9)
test%() = 4, 65, 2, -31, 0, 99, 2, 83, 782, 1
PROCradixsort(test%(), 10, 10)
FOR i% = 0 TO 9
PRINT test%(i%) ;
NEXT
PRINT
END
DEF PROCradixsort(a%(), n%, r%)
LOCAL d%, e%, i%, l%, m%, b%(), bucket%()
DIM b%(n%-1), bucket%(r%-1)
FOR i% = 0 TO n%-1
IF a%(i%) < l% l% = a%(i%)
IF a%(i%) > m% m% = a%(i%)
NEXT
a%() -= l%
m% -= l%
e% = 1
WHILE m% DIV e%
bucket%() = 0
FOR i% = 0 TO n%-1
bucket%(a%(i%) DIV e% MOD r%) += 1
NEXT
FOR i% = 1 TO r%-1
bucket%(i%) += bucket%(i% - 1)
NEXT
FOR i% = n%-1 TO 0 STEP -1
d% = a%(i%) DIV e% MOD r%
bucket%(d%) -= 1
b%(bucket%(d%)) = a%(i%)
NEXT
a%() = b%()
e% *= r%
ENDWHILE
a%() += l%
ENDPROC</lang>
Output:
-31 0 1 2 2 4 65 83 99 782
C
Radix sort, "digits" are most significant bits.<lang c>#include <stdio.h>
- include <limits.h>
- include <stdlib.h>
- include <time.h>
// Get size of statically allocated array
- define ARR_LEN(ARR) (sizeof ARR / sizeof *ARR)
// Generate random number in the interval [M,N]
- define RAND_RNG(M,N) (M + rand() / (RAND_MAX / (N - M + 1) + 1));
static void swap(unsigned *a, unsigned *b) {
unsigned tmp = *a; *a = *b; *b = tmp;
}
/* sort unsigned ints */ static void rad_sort_u(unsigned *from, unsigned *to, unsigned bit) { if (!bit || to < from + 1) return;
unsigned *ll = from, *rr = to - 1; for (;;) { /* find left most with bit, and right most without bit, swap */ while (ll < rr && !(*ll & bit)) ll++; while (ll < rr && (*rr & bit)) rr--; if (ll >= rr) break; swap(ll, rr); }
if (!(bit & *ll) && ll < to) ll++; bit >>= 1;
rad_sort_u(from, ll, bit); rad_sort_u(ll, to, bit); }
/* sort signed ints: flip highest bit, sort as unsigned, flip back */ static void radix_sort(int *a, const size_t len) { size_t i; unsigned *x = (unsigned*) a;
for (i = 0; i < len; i++)
x[i] ^= INT_MIN;
rad_sort_u(x, x + len, INT_MIN);
for (i = 0; i < len; i++)
x[i] ^= INT_MIN;
}
int main(void) {
srand(time(NULL)); int x[16];
for (size_t i = 0; i < ARR_LEN(x); i++)
x[i] = RAND_RNG(-128,127)
radix_sort(x, ARR_LEN(x));
for (size_t i = 0; i < ARR_LEN(x); i++)
printf("%d%c", x[i], i + 1 < ARR_LEN(x) ? ' ' : '\n');
}</lang>output
-182 -175 -151 -141 -70 -51 -20 -5 -1 41 70 103 171 198 227 242
C#
<lang csharp>using System;
namespace RadixSort {
class Program
{
static void Sort(int[] old)
{
int i, j;
int[] tmp = new int[old.Length];
for (int shift = 31; shift > -1; --shift)
{
j = 0;
for (i = 0; i < old.Length; ++i)
{
bool move = (old[i] << shift) >= 0;
if (shift == 0 ? !move : move) // shift the 0's to old's head
old[i-j] = old[i];
else // move the 1's to tmp
tmp[j++] = old[i];
}
Array.Copy(tmp, 0, old, old.Length-j, j);
}
}
static void Main(string[] args)
{
int[] old = new int[] { 2, 5, 1, -3, 4 };
Console.WriteLine(string.Join(", ", old));
Sort(old);
Console.WriteLine(string.Join(", ", old));
Console.Read();
}
}
}</lang>
C++
Implements a least significant digit radix sort and a recursive most significant digit radix sort.
Note: the LSD radix sort uses the standard library std::stable_partition algorithm. This algorithm is guaranteed to preserve relative order and has a higher runtime cost. The MSD radix sort uses std::partition and can be significantly faster. <lang cpp>#include <algorithm>
- include <iostream>
- include <iterator>
// Radix sort comparator for 32-bit two's complement integers class radix_test {
const int bit; // bit position [0..31] to examine
public:
radix_test(int offset) : bit(offset) {} // constructor
bool operator()(int value) const // function call operator
{
if (bit == 31) // sign bit
return value < 0; // negative int to left partition
else
return !(value & (1 << bit)); // 0 bit to left partition
}
};
// Least significant digit radix sort void lsd_radix_sort(int *first, int *last) {
for (int lsb = 0; lsb < 32; ++lsb) // least-significant-bit
{
std::stable_partition(first, last, radix_test(lsb));
}
}
// Most significant digit radix sort (recursive) void msd_radix_sort(int *first, int *last, int msb = 31) {
if (first != last && msb >= 0)
{
int *mid = std::partition(first, last, radix_test(msb));
msb--; // decrement most-significant-bit
msd_radix_sort(first, mid, msb); // sort left partition
msd_radix_sort(mid, last, msb); // sort right partition
}
}
// test radix_sort int main() {
int data[] = { 170, 45, 75, -90, -802, 24, 2, 66 };
lsd_radix_sort(data, data + 8); // msd_radix_sort(data, data + 8);
std::copy(data, data + 8, std::ostream_iterator<int>(std::cout, " "));
return 0;
}</lang> Output:
-802 -90 2 24 45 66 75 170
D
Shorter Version
<lang d>import std.stdio, std.math, std.traits, std.range, std.algorithm;
ElementType!R[] radixSort(size_t N=10, R)(R r) if (hasLength!R && isRandomAccessRange!R &&
isIntegral!(ElementType!R)) {
alias ElementType!R E;
static if (isDynamicArray!R)
alias r res; // input is array => in place sort
else
E[] res = r.array(); // input is Range => return a new array
E absMax = r.map!abs().reduce!max(); immutable nPasses = 1 + cast(int)(log(absMax) / log(N));
foreach (pass; 0 .. nPasses) {
auto bucket = new E[][](2 * N - 1, 0);
foreach (v; res) {
int bIdx = abs(v / (N ^^ pass)) % N;
bIdx = (v < 0) ? -bIdx : bIdx;
bucket[N + bIdx - 1] ~= v;
}
res = bucket.join();
}
return res;
}
void main() {
auto items = [170, 45, 75, -90, 2, 24, -802, 66];
items.radixSort().writeln();
items.map!q{1 - a}().radixSort().writeln();
}</lang>
- Output:
[-802, -90, 2, 24, 45, 66, 75, 170] [-1, -23, -44, -65, -74, -169, 91, 803]
More Efficient Version
<lang d>import std.array, std.traits;
// considered pure for this program extern(C) void* alloca(in size_t length) pure nothrow;
void radixSort(size_t MAX_ALLOCA=5_000, U)(U[] data) pure nothrow if (isUnsigned!U) {
static void radix(in uint byteIndex, in U[] source, U[] dest)
pure nothrow {
immutable size_t sourceSize = source.length;
ubyte* curByte = (cast(ubyte*)source.ptr) + byteIndex;
uint[ubyte.max + 1] byteCounter;
for (size_t i = 0; i < sourceSize; i++, curByte += U.sizeof)
byteCounter[*curByte]++;
{
uint indexStart;
foreach (uint i; 0 .. byteCounter.length) {
immutable size_t tempCount = byteCounter[i];
byteCounter[i] = indexStart;
indexStart += tempCount;
}
}
curByte = (cast(ubyte*)source.ptr) + byteIndex;
for (size_t i = 0; i < sourceSize; i++, curByte += U.sizeof) {
uint* countPtr = byteCounter.ptr + *curByte;
dest[*countPtr] = source[i];
(*countPtr)++;
}
}
U[] tempData;
if (U.sizeof * data.length <= MAX_ALLOCA) {
U* ptr = cast(U*)alloca(data.length * U.sizeof);
if (ptr != null)
tempData = ptr[0 .. data.length];
}
if (tempData.empty)
tempData = uninitializedArray!(U[])(data.length);
static if (U.sizeof == 1) {
radix(0, data, tempData);
data[] = tempData[];
} else {
for (uint i = 0; i < U.sizeof; i += 2) {
radix(i + 0, data, tempData);
radix(i + 1, tempData, data);
}
}
}
void main() {
import std.stdio; uint[] items = [170, 45, 75, 4294967206, 2, 24, 4294966494, 66]; items.radixSort(); writeln(items);
}</lang>
- Output:
[2, 24, 45, 66, 75, 170, 4294966494, 4294967206]
Original C++ code, modified (unknown license), by Andre Reinald, Paul Harris, Ryan Rohrer, Dirk Jagdmann: http://www.cubic.org/docs/download/radix_ar_2011.cpp
EasyLang
<lang># Radix sort - sorts positive integers
intvars subr sort
radix = 16
max = 0
for di range len data[]
if data[di] > max
max = data[di]
.
.
len buck[][] radix
pos = 1
while pos <= max
for i range radix
len buck[][i] 0
.
for di range len data[]
h = data[di] / pos mod radix
buck[][h] &= data[di]
.
di = 0
for i range radix
for j range len buck[][i]
data[di] = buck[j][i]
di += 1
.
.
pos *= radix
.
. data[] = [ 29 4 72 44 55 26 27 77 92 5 ] call sort print data[]</lang>
Eiffel
Works for positive integers. Splits up into two buckets according to the binary representation of the number. <lang Eiffel> class RADIX_SORT
feature
radix_sort (ar: ARRAY [INTEGER]) -- Array 'ar' sorted in ascending order. require ar_not_void: ar /= Void not_negative: across ar as a all a.item >= 0 end local bucket_1, bucket_0: LINKED_LIST [INTEGER] j, k, dig: INTEGER do create bucket_0.make create bucket_1.make dig := digits (ar) across 0 |..| dig as c loop across ar as r loop if r.item.bit_test (c.item) then bucket_1.extend (r.item) else bucket_0.extend (r.item) end end from j := 1 until j > bucket_0.count loop ar [j] := bucket_0 [j] j := j + 1 end from k := j j := 1 until j > bucket_1.count loop ar [k] := bucket_1 [j] k := k + 1 j := j + 1 end bucket_0.wipe_out bucket_1.wipe_out end ensure is_sorted: is_sorted (ar) end
feature {NONE}
digits (ar: ARRAY [INTEGER]): INTEGER -- Number of digits of the largest item in 'ar'. local max: INTEGER math: DOUBLE_MATH do create math across ar as a loop if a.item > max then max := a.item end end Result := math.log_2 (max).ceiling + 1 end
is_sorted (ar: ARRAY [INTEGER]): BOOLEAN --- Is 'ar' sorted in ascending order? 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 </lang> Test: <lang Eiffel> class APPLICATION
create make
feature
make local test: ARRAY [INTEGER] do create rs create test.make_empty test := <<5, 4, 999, 5, 70, 0, 1000, 55, 1, 2, 3>> io.put_string ("Unsorted:%N") across test as t loop io.put_string (t.item.out + " ") end rs.radix_sort (test) io.put_string ("%NSorted:%N") across test as t loop io.put_string (t.item.out + " ") end end
rs: RADIX_SORT
end </lang>
- Output:
Unsorted: 5 4 999 5 70 0 1000 55 1 2 3 Sorted: 0 1 2 3 4 5 5 55 70 999 1000
Elixir
<lang elixir>defmodule Sort do
def radix_sort(list), do: radix_sort(list, 10)
def radix_sort([], _), do: []
def radix_sort(list, base) do
max = abs(Enum.max_by(list, &abs(&1)))
sorted = radix_sort(list, base, max, 1)
{minus, plus} = Enum.partition(sorted, &(&1<0))
Enum.reverse(minus, plus)
end
defp radix_sort(list, _, max, m) when max<m, do: list
defp radix_sort(list, base, max, m) do
buckets = List.to_tuple(for _ <- 0..base-1, do: [])
bucket2 = Enum.reduce(list, buckets, fn x,acc ->
i = abs(x) |> div(m) |> rem(base)
put_elem(acc, i, [x | elem(acc, i)])
end)
list2 = Enum.reduce(base-1..0, [], fn i,acc -> Enum.reverse(elem(bucket2, i), acc) end)
radix_sort(list2, base, max, m*base)
end
end
IO.inspect Sort.radix_sort([-4, 5, -26, 58, -990, 331, 331, 990, -1837, 2028])</lang>
- Output:
[-1837, -990, -26, -4, 5, 58, 331, 331, 990, 2028]
Fortran
<lang Fortran>
- =======================================================================
- RSORT - sort a list of integers by the Radix Sort algorithm
- Public domain. This program may be used by any person for any purpose.
- Origin: Herman Hollerith, 1887
- ___Name____Type______In/Out____Description_____________________________
- IX(N) Integer Both Array to be sorted in increasing order
- IW(N) Integer Neither Workspace
- N Integer In Length of array
- ASSUMPTIONS: Bits in an INTEGER is an even number.
- Integers are represented by twos complement.
- NOTE THAT: Radix sorting has an advantage when the input is known
- to be less than some value, so that only a few bits need
- to be compared. This routine looks at all the bits,
- and is thus slower than Quicksort.
- =======================================================================
SUBROUTINE RSORT (IX, IW, N)
IMPLICIT NONE
INTEGER IX, IW, N
DIMENSION IX(N), IW(N)
INTEGER I, ! count bits
$ ILIM, ! bits in an integer
$ J, ! count array elements
$ P1OLD, P0OLD, P1, P0, ! indices to ones and zeros
$ SWAP
LOGICAL ODD ! even or odd bit position
- IF (N < 2) RETURN ! validate
ILIM = Bit_size(i) !Get the fixed number of bits
- =======================================================================
- Alternate between putting data into IW and into IX
- =======================================================================
P1 = N+1
P0 = N ! read from 1, N on first pass thru
ODD = .FALSE.
DO I = 0, ILIM-2
P1OLD = P1
P0OLD = P0 ! save the value from previous bit
P1 = N+1
P0 = 0 ! start a fresh count for next bit
IF (ODD) THEN
DO J = 1, P0OLD, +1 ! copy data from the zeros
IF ( BTEST(IW(J), I) ) THEN
P1 = P1 - 1
IX(P1) = IW(J)
ELSE
P0 = P0 + 1
IX(P0) = IW(J)
END IF
END DO
DO J = N, P1OLD, -1 ! copy data from the ones
IF ( BTEST(IW(J), I) ) THEN
P1 = P1 - 1
IX(P1) = IW(J)
ELSE
P0 = P0 + 1
IX(P0) = IW(J)
END IF
END DO
ELSE
DO J = 1, P0OLD, +1 ! copy data from the zeros
IF ( BTEST(IX(J), I) ) THEN
P1 = P1 - 1
IW(P1) = IX(J)
ELSE
P0 = P0 + 1
IW(P0) = IX(J)
END IF
END DO
DO J = N, P1OLD, -1 ! copy data from the ones
IF ( BTEST(IX(J), I) ) THEN
P1 = P1 - 1
IW(P1) = IX(J)
ELSE
P0 = P0 + 1
IW(P0) = IX(J)
END IF
END DO
END IF ! even or odd i
ODD = .NOT. ODD
END DO ! next i
- =======================================================================
- the sign bit
- =======================================================================
P1OLD = P1
P0OLD = P0
P1 = N+1
P0 = 0
- if sign bit is set, send to the zero end
DO J = 1, P0OLD, +1
IF ( BTEST(IW(J), ILIM-1) ) THEN
P0 = P0 + 1
IX(P0) = IW(J)
ELSE
P1 = P1 - 1
IX(P1) = IW(J)
END IF
END DO
DO J = N, P1OLD, -1
IF ( BTEST(IW(J), ILIM-1) ) THEN
P0 = P0 + 1
IX(P0) = IW(J)
ELSE
P1 = P1 - 1
IX(P1) = IW(J)
END IF
END DO
- =======================================================================
- Reverse the order of the greater value partition
- =======================================================================
P1OLD = P1
DO J = N, (P1OLD+N)/2+1, -1
SWAP = IX(J)
IX(J) = IX(P1)
IX(P1) = SWAP
P1 = P1 + 1
END DO
RETURN
END ! of RSORT
- test program
PROGRAM t_sort
IMPLICIT NONE
INTEGER I, N
PARAMETER (N = 11)
INTEGER IX(N), IW(N)
LOGICAL OK
DATA IX / 2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666 /
PRINT *, 'before: ', IX
CALL RSORT (IX, IW, N)
PRINT *, 'after: ', IX
- compare
OK = .TRUE.
DO I = 1, N-1
IF (IX(I) > IX(I+1)) OK = .FALSE.
END DO
IF (OK) THEN
PRINT *, 't_sort: successful test'
ELSE
PRINT *, 't_sort: failure!'
END IF
END ! of test program
</lang>
- Output:
before: 2 24 45 0 66 75 170 -802 -90 1066 666 after: -802 -90 0 2 24 45 66 75 170 666 1066 t_sort: successful test
Go
LSD radix 256, negatives handled by flipping the high bit. <lang go>package main
import (
"bytes" "encoding/binary" "fmt"
)
// declarations for word size of data type word int32 const wordLen = 4 const highBit = -1 << 31
var data = []word{170, 45, 75, -90, -802, 24, 2, 66}
func main() {
buf := bytes.NewBuffer(nil)
ds := make([][]byte, len(data))
for i, x := range data {
binary.Write(buf, binary.LittleEndian, x^highBit)
b := make([]byte, wordLen)
buf.Read(b)
ds[i] = b
}
bins := make([][][]byte, 256)
for i := 0; i < wordLen; i++ {
for _, b := range ds {
bins[b[i]] = append(bins[b[i]], b)
}
j := 0
for k, bs := range bins {
copy(ds[j:], bs)
j += len(bs)
bins[k] = bs[:0]
}
}
fmt.Println("original:", data)
var w word
for i, b := range ds {
buf.Write(b)
binary.Read(buf, binary.LittleEndian, &w)
data[i] = w^highBit
}
fmt.Println("sorted: ", data)
}</lang> Output:
original: [170 45 75 -90 -802 24 2 66] sorted: [-802 -90 2 24 45 66 75 170]
Groovy
This solution assumes the radix is a power of 2: <lang groovy>def radixSort = { final radixExponent, list ->
def fromBuckets = new TreeMap([0:list])
def toBuckets = new TreeMap()
final radix = 2**radixExponent
final mask = radix - 1
final radixDigitSize = (int)Math.ceil(64/radixExponent)
final digitWidth = radixExponent
(0..<radixDigitSize).each { radixDigit ->
fromBuckets.values().findAll { it != null }.flatten().each {
print '.'
long bucketNumber = (long)((((long)it) >>> digitWidth*radixDigit) & mask)
toBuckets[bucketNumber] = toBuckets[bucketNumber] ?: []
toBuckets[bucketNumber] << it
}
(fromBuckets, toBuckets) = [toBuckets, fromBuckets]
toBuckets.clear()
}
final overflow = 2**(63 % radixExponent)
final pos = {it < overflow}
final neg = {it >= overflow}
final keys = fromBuckets.keySet()
final twosComplIndx = [] + (keys.findAll(neg)) + (keys.findAll(pos))
twosComplIndx.collect { fromBuckets[it] }.findAll { it != null }.flatten()
}</lang>
Test: <lang groovy>println (radixSort(3, [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4])) println (radixSort(3, [88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])) println (radixSort(3, [23,-76,-990,580,97,57,350000,Long.MAX_VALUE,89,Long.MIN_VALUE,51,38,95*2**48,92,-24*2**48,46,31*2**32,24,14,12,57,78,4])) println () println (radixSort(8, [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4])) println (radixSort(8, [88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])) println (radixSort(8, [23,-76,-990,580,97,57,350000,Long.MAX_VALUE,89,Long.MIN_VALUE,51,38,95*2**48,92,-24*2**48,46,31*2**32,24,14,12,57,78,4])) println () println (radixSort(11, [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4])) println (radixSort(11, [88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])) println (radixSort(11, [23,-76,-990,580,97,57,350000,Long.MAX_VALUE,89,Long.MIN_VALUE,51,38,95*2**48,92,-24*2**48,46,31*2**32,24,14,12,57,78,4])) println () println (radixSort(16, [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4])) println (radixSort(16, [88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])) println (radixSort(16, [23,-76,-990,580,97,57,350000,Long.MAX_VALUE,89,Long.MIN_VALUE,51,38,95*2**48,92,-24*2**48,46,31*2**32,24,14,12,57,78,4])) println () println (radixSort(32, [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4])) println (radixSort(32, [88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])) println (radixSort(32, [23,-76,-990,580,97,57,350000,Long.MAX_VALUE,89,Long.MIN_VALUE,51,38,95*2**48,92,-24*2**48,46,31*2**32,24,14,12,57,78,4]))</lang>
Output:
..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................[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] ..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[-9223372036854775808, -6755399441055744, -990, -76, 4, 12, 14, 23, 24, 38, 46, 51, 57, 57, 78, 89, 92, 97, 580, 350000, 133143986176, 26740122787512320, 9223372036854775807] ........................................................................................................................................................................[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] ........................................................................................................................................................................................[-9223372036854775808, -6755399441055744, -990, -76, 4, 12, 14, 23, 24, 38, 46, 51, 57, 57, 78, 89, 92, 97, 580, 350000, 133143986176, 26740122787512320, 9223372036854775807] ..............................................................................................................................[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] ..........................................................................................................................................[-9223372036854775808, -6755399441055744, -990, -76, 4, 12, 14, 23, 24, 38, 46, 51, 57, 57, 78, 89, 92, 97, 580, 350000, 133143986176, 26740122787512320, 9223372036854775807] ....................................................................................[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] ............................................................................................[-9223372036854775808, -6755399441055744, -990, -76, 4, 12, 14, 23, 24, 38, 46, 51, 57, 57, 78, 89, 92, 97, 580, 350000, 133143986176, 26740122787512320, 9223372036854775807] ..........................................[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] ..............................................[-9223372036854775808, -6755399441055744, -990, -76, 4, 12, 14, 23, 24, 38, 46, 51, 57, 57, 78, 89, 92, 97, 580, 350000, 133143986176, 26740122787512320, 9223372036854775807]
Haskell
<lang haskell>import Data.Bits (Bits(testBit, bitSize)) import Data.List (partition)
lsdSort :: (Ord a, Bits a) => [a] -> [a] lsdSort = fixSort positiveLsdSort
msdSort :: (Ord a, Bits a) => [a] -> [a] msdSort = fixSort positiveMsdSort
-- Fix a sort that puts negative numbers at the end, like positiveLsdSort and positiveMsdSort fixSort sorter list = uncurry (flip (++)) (break (< 0) (sorter list))
positiveLsdSort :: (Bits a) => [a] -> [a] positiveLsdSort list = foldl step list [0..bitSize (head list)] where step list bit = uncurry (++) (partition (not . flip testBit bit) list)
positiveMsdSort :: (Bits a) => [a] -> [a] positiveMsdSort list = aux (bitSize (head list) - 1) list where aux _ [] = [] aux (-1) list = list aux bit list = aux (bit - 1) lower ++ aux (bit - 1) upper where (lower, upper) = partition (not . flip testBit bit) list</lang>
Icon and Unicon
The following is nice and short and works in both languages. However it contains a subtle inefficiency: subscripting a numeric value first coerces it into a string.
<lang unicon>procedure main(A)
every writes((!rSort(A)||" ")|"\n")
end
procedure rSort(A)
every (min := A[1]) >:= !A
every (mlen := *(A[1]-min)) <:= (!A - min)
every i := !*mlen do {
every put(b := [], |[]\12)
every a := !A do put(b[(a-min)[-i]+2|1], a)
every put(A := [],!!b)
}
return A
end</lang>
Sample run:
->radix 31 123 -98 7090 802 2 -98 2 31 123 802 7090 ->
J
keys f/. data evaluates the function f on each group of data at the same position as similar keys. Sorting requires ordered keys. This code uses a J idiom: prepend the keys and matching data. The extra data is removed by behead }..
<lang j> radixSortR =: 3 : 0 NB. base radixSort data 16 radixSortR y
keys =. x #.^:_1 y NB. compute keys length =. #{.keys extra =. (-length) {."0 buckets =. i.x for_pass. i.-length do.
keys =. ; (buckets,pass{"1 keys) <@:}./.extra,keys
end. x#.keys NB. restore the data )</lang>
An alternate implementation is <lang j>radixsort=: (] #~ [: +/ =/) i.@(>./)</lang>
This uses the maximum value of the list for the base, which allows the list to be sorted in one pass.
Example use:
<lang j> radixsort ?.@#~10 4 5 6 6 6 6 6 8 8</lang>
Or, for negative number support:
<lang j>rsort=: (] + radixsort@:-) <./</lang>
Example:
<lang j> rsort _6+?.@#~10 _2 _1 0 0 0 0 0 2 2</lang>
Java
<lang java>public static int[] sort(int[] old) {
// Loop for every bit in the integers
for (int shift = Integer.SIZE - 1; shift > -1; shift--) {
// The array to put the partially sorted array into
int[] tmp = new int[old.length];
// The number of 0s
int j = 0;
// Move the 0s to the new array, and the 1s to the old one
for (int i = 0; i < old.length; i++) {
// If there is a 1 in the bit we are testing, the number will be negative
boolean move = old[i] << shift >= 0;
// If this is the last bit, negative numbers are actually lower
if (shift == 0 ? !move : move) {
tmp[j] = old[i];
j++;
} else {
// It's a 1, so stick it in the old array for now
old[i - j] = old[i];
}
}
// Copy over the 1s from the old array
for (int i = j; i < tmp.length; i++) {
tmp[i] = old[i - j];
}
// And now the tmp array gets switched for another round of sorting
old = tmp;
}
return old;
}</lang>
<lang Java> import java.util.ArrayList; import java.util.Arrays; import java.util.LinkedList; import java.util.List; import java.util.Queue;
public class RSortingRadixsort00 {
public RSortingRadixsort00() {
return; }
public static int[] lsdRadixSort(int[] tlist) {
List<Integer> intermediates; int[] limits = getLimits(tlist); tlist = rescale(tlist, limits[1]);
for (int px = 1; px <= limits[2]; ++px) {
@SuppressWarnings("unchecked")
Queue<Integer> bukits[] = new Queue[10];
for (int ix = 0; ix < tlist.length; ++ix) {
int cval = tlist[ix];
int digit = (int) (cval / Math.pow(10, px - 1) % 10);
if (bukits[digit] == null) {
bukits[digit] = new LinkedList<>();
}
bukits[digit].add(cval);
}
intermediates = new ArrayList<>();
for (int bi = 0; bi < 10; ++bi) {
if (bukits[bi] != null) {
while (bukits[bi].size() > 0) {
int nextd;
nextd = bukits[bi].poll();
intermediates.add(nextd);
}
}
}
for (int iw = 0; iw < intermediates.size(); ++iw) {
tlist[iw] = intermediates.get(iw);
}
}
tlist = rescale(tlist, -limits[1]);
return tlist; }
private static int[] rescale(int[] arry, int delta) {
for (int ix = 0; ix < arry.length; ++ix) {
arry[ix] -= delta;
}
return arry; }
private static int[] getLimits(int[] tlist) {
int[] lims = new int[3];
for (int i_ = 0; i_ < tlist.length; ++i_) {
lims[0] = Math.max(lims[0], tlist[i_]);
lims[1] = Math.min(lims[1], tlist[i_]);
}
lims[2] = (int) Math.ceil(Math.log10(lims[0] - lims[1]));
return lims; }
private static void runSample(String[] args) {
int[][] lists = {
new int[] { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, },
new int[] { -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, -0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, },
new int[] { 2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666, },
new int[] { 170, 45, 75, 90, 2, 24, 802, 66, },
new int[] { -170, -45, -75, -90, -2, -24, -802, -66, },
};
long etime; lsdRadixSort(Arrays.copyOf(lists[0], lists[0].length)); // do one pass to set up environment to remove it from timings
for (int[] tlist : lists) {
System.out.println(array2list(tlist));
etime = System.nanoTime();
tlist = lsdRadixSort(tlist);
etime = System.nanoTime() - etime;
System.out.println(array2list(tlist));
System.out.printf("Elapsed time: %fs%n", ((double) etime / 1_000_000_000.0));
System.out.println();
}
return; }
private static List<Integer> array2list(int[] arry) {
List<Integer> target = new ArrayList<>(arry.length);
for (Integer iv : arry) {
target.add(iv);
}
return target; }
public static void main(String[] args) {
runSample(args);
return; }
} </lang>
- Output:
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10] [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Elapsed time: 0.000256s [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Elapsed time: 0.000198s [2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666] [-802, -90, 0, 2, 24, 45, 66, 75, 170, 666, 1066] Elapsed time: 0.000187s [170, 45, 75, 90, 2, 24, 802, 66] [2, 24, 45, 66, 75, 90, 170, 802] Elapsed time: 0.000088s [-170, -45, -75, -90, -2, -24, -802, -66] [-802, -170, -90, -75, -66, -45, -24, -2] Elapsed time: 0.000113s
jq
<lang jq># Sort the input array;
- "base" must be an integer greater than 1
def radix_sort(base):
# We only need the ceiling of non-negatives: def ceil: if . == floor then . else (. + 1 | floor) end;
min as $min
| map(. - $min)
| ((( max|log) / (base|log)) | ceil) as $rounds
| reduce range(0; $rounds) as $i
# state: [ base^i, buckets ]
( [1, .];
.[0] as $base_i
| reduce .[1][] as $n
([];
(($n/$base_i) % base) as $digit
| .[$digit] += [$n] )
| [($base_i * base), (map(select(. != null)) | flatten)] )
| .[1]
| map(. + $min) ;
def radix_sort:
radix_sort(10);
</lang> Example <lang jq>
- Verify that radix_sort agrees with sort
( [1, 3, 8, 9, 0, 0, 8, 7, 1, 6],
[170, 45, 75, 90, 2, 24, 802, 66], [170, 45, 75, 90, 2, 24, -802, -66] )
| (radix_sort == sort) </lang>
- Output:
true true true
Julia
<lang julia>function radixsort(tobesorted::Vector{Int64})
arr = deepcopy(tobesorted)
for shift in 63:-1:0
tmp = Vector{Int64}(undef, length(arr))
j = 0
for i in 1:length(arr)
if (shift == 0) == ((arr[i] << shift) >= 0)
arr[i - j] = arr[i]
else
tmp[j + 1] = arr[i]
j += 1
end
end
tmp[j+1:end] .= arr[1:length(tmp)-j]
arr = tmp
end
arr
end
function testradixsort()
arrays = [[170, 45, 75, -90, -802, 24, 2, 66], [-4, 5, -26, 58, -990, 331, 331, 990, -1837, 2028]]
for array in arrays
println(radixsort(array))
end
end
testradixsort()
</lang>
- Output:
[-802, -90, 2, 24, 45, 66, 75, 170] [-1837, -990, -26, -4, 5, 58, 331, 331, 990, 2028]
Kotlin
<lang scala>// version 1.1.2
fun radixSort(original: IntArray): IntArray {
var old = original // Need this to be mutable
// Loop for every bit in the integers
for (shift in 31 downTo 0) {
val tmp = IntArray(old.size) // The array to put the partially sorted array into
var j = 0 // The number of 0s
// Move the 0s to the new array, and the 1s to the old one
for (i in 0 until old.size) {
// If there is a 1 in the bit we are testing, the number will be negative
val move = (old[i] shl shift) >= 0
// If this is the last bit, negative numbers are actually lower
val toBeMoved = if (shift == 0) !move else move
if (toBeMoved)
tmp[j++] = old[i]
else {
// It's a 1, so stick it in the old array for now
old[i - j] = old[i]
}
}
// Copy over the 1s from the old array
for (i in j until tmp.size) tmp[i] = old[i - j]
// And now the tmp array gets switched for another round of sorting
old = tmp
}
return old
}
fun main(args: Array<String>) {
val arrays = arrayOf(
intArrayOf(170, 45, 75, -90, -802, 24, 2, 66),
intArrayOf(-4, 5, -26, 58, -990, 331, 331, 990, -1837, 2028)
)
for (array in arrays) println(radixSort(array).contentToString())
}</lang>
- Output:
[-802, -90, 2, 24, 45, 66, 75, 170] [-1837, -990, -26, -4, 5, 58, 331, 331, 990, 2028]
Mathematica
<lang Mathematica>ClearAll[SortByPos, RadixSort] SortByPos[data : {_List ..}, pos_Integer] := Module[{digs, order},
digs = dataAll, pos; order = Ordering[digs]; dataorder ]
RadixSort[x : {_Integer ..}] := Module[{y, digs, maxlen, offset},
offset = Min[x]; y = x - offset; digs = IntegerDigits /@ y; maxlen = Max[Length /@ digs]; digs = IntegerDigits[#, 10, maxlen] & /@ y; digs = Fold[SortByPos, digs, -Range[maxlen]]; digs = FromDigits /@ digs; digs += offset; digs ]</lang>
Testing out the algorithm: <lang Mathematica>RadixSort[{170,45,75,-90,-802,24,2,66}] RadixSort[{170,45,75,90,802,2,24,66}]</lang>
- Output:
{-802,-90,2,24,45,66,75,170}
{2,24,45,66,75,90,170,802}
NetRexx
Uses a suggestion in the discussion page to handle negative values.
Limitations - Handles decimal digits only.
Using the Rexx class
<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary
runSample(arg) return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method radixSort(tlist = Rexx[]) public static returns Rexx[]
-- scale the array to start at zero to allow handling of -ve values parse getLimits(tlist) maxn minn maxl . tlist = rescale(tlist, minn)
loop px = maxl to 1 by -1
bukits =
loop ix = 0 to tlist.length - 1
cval = tlist[ix].right(maxl, 0)
parse cval . =(px) digit +1 .
bukits[digit] = bukits[digit] (cval + 0) -- simulates a stack
end ix
intermediates =
loop bi = 0 to 9
intermediates = intermediates bukits[bi] -- sumulates unstack
end bi
-- reload array
loop iw = 1 to intermediates.words()
tlist[iw - 1] = intermediates.word(iw)
end iw
end px
-- restore the array to original scale tlist = rescale(tlist, -minn) return tlist
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method rescale(arry = Rexx[], newbase) private static returns Rexx[]
loop ix = 0 to arry.length - 1 arry[ix] = arry[ix] - newbase end ix return arry
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method getLimits(arry = Rexx[]) private static returns Rexx
maxn = 0 minn = 0 maxl = 0 loop i_ = 0 to arry.length - 1 maxn = maxn.max(arry[i_]) minn = minn.min(arry[i_]) end i_ maxl = (maxn - minn).length() return maxn minn maxl
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method runSample(arg) private static
lists = [- [2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666], - [170, 45, 75, 90, 2, 24, 802, 66], - [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0], - [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], - [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, -0], - [-0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10], - [-10, -19, -18, -17, -18, -15, -14, -13, -12, -11, -100], - [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0, -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10], - [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, -0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] - ]
loop il = 0 to lists.length - 1 tlist = lists[il] say ' Input:' Arrays.asList(tlist) say 'Output:' Arrays.asList(radixSort(tlist)) say end il return
</lang>
- Output:
Input: [2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666] Output: [-802, -90, 0, 2, 24, 45, 66, 75, 170, 666, 1066] Input: [170, 45, 75, 90, 2, 24, 802, 66] Output: [2, 24, 45, 66, 75, 90, 170, 802] Input: [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0] Output: [0, 1, 2, 3, 4, 5, 7, 8, 8, 9, 10] Input: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Output: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Input: [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, 0] Output: [-10, -9, -8, -8, -7, -5, -4, -3, -2, -1, 0] Input: [0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10] Output: [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0] Input: [-10, -19, -18, -17, -18, -15, -14, -13, -12, -11, -100] Output: [-100, -19, -18, -18, -17, -15, -14, -13, -12, -11, -10] Input: [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0, 0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10] Output: [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 7, 8, 8, 9, 10] Input: [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Output: [-10, -9, -8, -8, -7, -5, -4, -3, -2, -1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Using Collection classes
<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary
import java.util.Queue
runSample(arg) return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method radixSort(tlist = Rexx[]) public static returns Rexx[]
-- scale the array to start at zero to allow handling of -ve values limits = parse '!MAXN !MINN !MAXL' maxn_ minn_ maxl_ . parse getLimits(tlist) maxn minn maxl . limits[maxn_] = maxn limits[minn_] = minn limits[maxl_] = maxl tlist = rescale(tlist, limits[minn_])
loop px = limits[maxl_] to 1 by -1
bukits = Queue[10] -- stacks for digits 0 .. 9
loop ix = 0 while ix < tlist.length
cval = tlist[ix].right(limits[maxl_], 0)
parse cval . =(px) digit +1 . -- extract next digit (fun with parse)
-- alternatively: digit = (cval % (10 ** (px - 1))) // 10
if bukits[digit] == null then bukits[digit] = LinkedList()
bukits[digit].add((cval + 0))
end ix
intermediates = ArrayList()
loop bi = 0 to 9
if bukits[bi] \= null then loop while bukits[bi].size() > 0
nextd = bukits[bi].poll()
intermediates.add(nextd)
end
end bi
-- reload result array
loop iw = 0 while iw < intermediates.size()
tlist[iw] = Rexx intermediates.get(iw)
end iw
end px
-- restore the array to original scale tlist = rescale(tlist, -limits[minn_]) return tlist
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method rescale(arry = Rexx[], newbase) private static returns Rexx[]
loop ix = 0 to arry.length - 1 arry[ix] = arry[ix] - newbase end ix return arry
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method getLimits(arry = Rexx[]) private static returns Rexx
maxn = 0 minn = 0 maxl = 0 loop i_ = 0 to arry.length - 1 maxn = maxn.max(arry[i_]) minn = minn.min(arry[i_]) end i_ maxl = (maxn - minn).length() return maxn minn maxl
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method runSample(arg) private static
lists = [- [2, 24, 45, 0, 66, 75, 170, -802, -90, 1066, 666], - [170, 45, 75, 90, 2, 24, 802, 66], - [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0], - [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], - [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, -0], - [-0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10], - [-10, -19, -18, -17, -18, -15, -14, -13, -12, -11, -100], - [10, 9, 8, 7, 8, 5, 4, 3, 2, 1, 0, -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10], - [-10, -9, -8, -7, -8, -5, -4, -3, -2, -1, -0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] - ]
loop il = 0 to lists.length - 1 tlist = lists[il] say ' Input:' Arrays.asList(tlist) say 'Output:' Arrays.asList(radixSort(tlist)) say end il return
</lang>
Perl
Radix sort in base 10. <lang perl>#!/usr/bin/perl use warnings; use strict;
sub radix {
my @tab = ([@_]);
my $max_length = 0;
length > $max_length and $max_length = length for @_;
$_ = sprintf "%0${max_length}d", $_ for @{ $tab[0] }; # Add zeros.
for my $pos (reverse -$max_length .. -1) {
my @newtab;
for my $bucket (@tab) {
for my $n (@$bucket) {
my $char = substr $n, $pos, 1;
$char = -1 if '-' eq $char;
$char++;
push @{ $newtab[$char] }, $n;
}
}
@tab = @newtab;
}
my @return;
my $negative = shift @tab; # Negative bucket must be reversed.
push @return, reverse @$negative;
for my $bucket (@tab) {
push @return, @{ $bucket // [] };
}
$_ = 0 + $_ for @return; # Remove zeros.
return @return;
}</lang> To test, add the following lines: <lang perl>use Test::More tests => 1000;
for (1 .. 1000) {
my @l = map int rand(2000) - 1000, 0 .. 20;
is_deeply([radix(@l)], [sort { $a <=> $b } @l]);
}</lang>
Phix
<lang Phix>function radixSortn(sequence s, integer n) sequence buckets = repeat({},10) sequence res = {}
for i=1 to length(s) do
integer digit = remainder(floor(s[i]/power(10,n-1)),10)+1
buckets[digit] = append(buckets[digit],s[i])
end for
for i=1 to length(buckets) do
integer len = length(buckets[i])
if len!=0 then
if len=1 or n=1 then
res &= buckets[i]
else
res &= radixSortn(buckets[i],n-1)
end if
end if
end for
return res
end function
function split_by_sign(sequence s) sequence buckets = {{},{}}
for i=1 to length(s) do
integer si = s[i]
if si<0 then
buckets[1] = append(buckets[1],-si)
else
buckets[2] = append(buckets[2],si)
end if
end for
return buckets
end function
function radixSort(sequence s) integer mins = min(s) integer passes = max(max(s),abs(mins))
passes = floor(log10(passes))+1
if mins<0 then
sequence buckets = split_by_sign(s)
buckets[1] = reverse(sq_uminus(radixSortn(buckets[1],passes)))
buckets[2] = radixSortn(buckets[2],passes)
s = buckets[1]&buckets[2]
else
s = radixSortn(s,passes)
end if
return s
end function
?radixSort({1, 3, 8, 9, 0, 0, 8, 7, 1, 6}) ?radixSort({170, 45, 75, 90, 2, 24, 802, 66}) ?radixSort({170, 45, 75, 90, 2, 24, -802, -66}) ?radixSort({100000, -10000, 400, 23, 10000})</lang>
- Output:
{0,0,1,1,3,6,7,8,8,9}
{2,24,45,66,75,90,170,802}
{-802,-66,2,24,45,75,90,170}
{-10000,23,400,10000,100000}
PicoLisp
This is a LSD base-2 radix sort using queues: <lang PicoLisp>(de radixSort (Lst)
(let Mask 1
(while
(let (Pos (list NIL NIL) Neg (list NIL NIL) Flg)
(for N Lst
(queue
(if2 (ge0 N) (bit? Mask N)
(cdr Pos) Pos Neg (cdr Neg) )
N )
(and (>= (abs N) Mask) (on Flg)) )
(setq
Lst (conc (apply conc Neg) (apply conc Pos))
Mask (* 2 Mask) )
Flg ) ) )
Lst )</lang>
Output:
: (radixSort (make (do 12 (link (rand -999 999))))) -> (-999 -930 -666 -336 -218 68 79 187 391 405 697 922)
PureBasic
<lang PureBasic>Structure bucket
List i.i()
EndStructure
DataSection
;sets specify the size (1 based) followed by each integer set1: Data.i 10 ;size Data.i 1, 3, 8, 9, 0, 0, 8, 7, 1, 6 ;data set2: Data.i 8 Data.i 170, 45, 75, 90, 2, 24, 802, 66 set3: Data.i 8 Data.i 170, 45, 75, 90, 2, 24, -802, -66
EndDataSection
Procedure setIntegerArray(Array x(1), *setPtr)
Protected i, count count = PeekI(*setPtr) - 1 ;convert to zero based count *setPtr + SizeOf(Integer) ;move pointer forward to data Dim x(count) For i = 0 To count x(i) = PeekI(*setPtr + i * SizeOf(Integer)) Next
EndProcedure
Procedure displayArray(Array x(1))
Protected i, Size = ArraySize(x())
For i = 0 To Size
Print(Str(x(i)))
If i < Size: Print(", "): EndIf
Next
PrintN("")
EndProcedure
Procedure radixSort(Array x(1), Base = 10)
Protected count = ArraySize(x())
If Base < 1 Or count < 1: ProcedureReturn: EndIf ;exit due to invalid values
Protected i, pv, digit, digitCount, maxAbs, pass, index
;find element with largest number of digits
For i = 0 To count
If Abs(x(i)) > maxAbs
maxAbs = Abs(x(i))
EndIf
Next
digitCount = Int(Log(maxAbs)/Log(Base)) + 1
For pass = 1 To digitCount
Dim sortBuckets.bucket(Base * 2 - 1)
pv = Pow(Base, pass - 1)
;place elements in buckets according to the current place-value's digit
For index = 0 To count
digit = Int(x(index)/pv) % Base + Base
AddElement(sortBuckets(digit)\i())
sortBuckets(digit)\i() = x(index)
Next
;transfer contents of buckets back into array
index = 0
For digit = 1 To (Base * 2) - 1
ForEach sortBuckets(digit)\i()
x(index) = sortBuckets(digit)\i()
index + 1
Next
Next
Next
EndProcedure
If OpenConsole()
Dim x(0) setIntegerArray(x(), ?set1) radixSort(x()): displayArray(x()) setIntegerArray(x(), ?set2) radixSort(x()): displayArray(x()) setIntegerArray(x(), ?set3) radixSort(x(), 2): displayArray(x()) Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole()
EndIf</lang> Sample output:
0, 0, 1, 1, 3, 6, 7, 8, 8, 9 2, 24, 45, 66, 75, 90, 170, 802 -802, -66, 2, 24, 45, 75, 90, 170
Python
This is the Wikipedia example code extended with an extra pass to sort negative values correctly.
<lang python>#python2.6 < from math import log
def getDigit(num, base, digit_num):
# pulls the selected digit return (num // base ** digit_num) % base
def makeBlanks(size):
# create a list of empty lists to hold the split by digit return [ [] for i in range(size) ]
def split(a_list, base, digit_num):
buckets = makeBlanks(base)
for num in a_list:
# append the number to the list selected by the digit
buckets[getDigit(num, base, digit_num)].append(num)
return buckets
- concatenate the lists back in order for the next step
def merge(a_list):
new_list = []
for sublist in a_list:
new_list.extend(sublist)
return new_list
def maxAbs(a_list):
# largest abs value element of a list return max(abs(num) for num in a_list)
def split_by_sign(a_list):
# splits values by sign - negative values go to the first bucket,
# non-negative ones into the second
buckets = [[], []]
for num in a_list:
if num < 0:
buckets[0].append(num)
else:
buckets[1].append(num)
return buckets
def radixSort(a_list, base):
# there are as many passes as there are digits in the longest number
passes = int(round(log(maxAbs(a_list), base)) + 1)
new_list = list(a_list)
for digit_num in range(passes):
new_list = merge(split(new_list, base, digit_num))
return merge(split_by_sign(new_list))
</lang>
An alternate implementation using which works on Python 3:
<lang python>#python3.7 < def flatten(some_list):
"""
Flatten a list of lists.
Usage: flatten([[list a], [list b], ...])
Output: [elements of list a, elements of list b]
"""
new_list = []
for sub_list in some_list:
new_list += sub_list
return new_list
def radix(some_list, idex=None, size=None):
"""
Recursive radix sort
Usage: radix([unsorted list])
Output: [sorted list]
"""
# Initialize variables not set in the initial call
if size == None:
largest_num = max(some_list)
largest_num_str = str(largest_num)
largest_num_len = len(largest_num_str)
size = largest_num_len
if idex == None:
idex = size
# Translate the index we're looking at into an array index. # e.g., looking at the 10's place for 100: # size: 3 # idex: 2 # i: (3-2) == 1 # str(123)[i] -> 2 i = size - idex
# The recursive base case.
# Hint: out of range indexing errors
if i >= size:
return some_list
# Initialize the bins we will place numbers into bins = [[] for _ in range(10)]
# Iterate over the list of numbers we are given
for e in some_list:
# The destination bin; e.g.,:
# size: 5
# e: 29
# num_s: '00029'
# i: 3
# dest_c: '2'
# dest_i: 2
num_s = str(e).zfill(size)
dest_c = num_s[i]
dest_i = int(dest_c)
bins[dest_i] += [e]
result = []
for b in bins:
#If the bin is empty it skips the recursive call
if b == []:
continue
# Make the recursive call
# Sort each of the sub-lists in our bins
result.append(radix(b, idex-1, size))
# Flatten our list # This is also called in our recursive call, # so we don't need flatten to be recursive. flattened_result = flatten(result)
return flattened_result
</lang>
That same example but more compact:
<lang python>#python3.7 < def flatten(l):
return [y for x in l for y in x]
def radix(l, p=None, s=None):
if s == None:
s = len(str(max(l)))
if p == None:
p = s
i = s - p
if i >= s:
return l
bins = [[] for _ in range(10)]
for e in l:
bins[int(str(e).zfill(s)[i])] += [e]
return flatten([radix(b, p-1, s) for b in bins]
</lang>
QB64
<lang QB64>
- lang QB64
'* don't be an a$$. Keep this credit notice with the source: '* written/refactored by CodeGuy, 2018. '* also works with negative numbers. TESTN& = 63 A$ = "" REDIM b(0 TO TESTN&) AS DOUBLE FOR s& = -1 TO 1 STEP 2
A$ = A$ + CHR$(13) + CHR$(10) + "Random order:"
FOR i = 0 TO TESTN&
b(i) = (1000 * RND) AND 1023
IF i MOD 2 THEN b(i) = -b(i)
IF i < TESTN& THEN
A$ = A$ + LTRIM$(STR$(b(i))) + ","
ELSE
A$ = A$ + LTRIM$(STR$(b(i))) + CHR$(13) + CHR$(10)
END IF
NEXT
RadixSort b(), 0, TESTN&, s&
IF s& = -1 THEN
A$ = A$ + "descending order" + CHR$(13) + CHR$(10)
ELSE
A$ = A$ + "ascending order" + CHR$(13) + CHR$(10)
END IF
FOR i = 0 TO TESTN&
PRINT b(i);
IF i < TESTN& THEN
A$ = A$ + LTRIM$(STR$(b(i))) + ","
ELSE
A$ = A$ + LTRIM$(STR$(b(i))) + CHR$(13) + CHR$(10)
END IF
NEXT
NEXT PRINT A$ TYPE MinMaxRec
min AS LONG max AS LONG
END TYPE
SUB RadixSort (CGSortLibArr() AS DOUBLE, start&, finish&, order&)
ArrayIsInteger CGSortLibArr(), start&, finish&, errindex&, errcon&
IF errcon& THEN
'* use another stable sort and sort anyway
MergeSort CGSortLibArr(), start&, finish&, order&
ELSE
DIM RSMMrec AS MinMaxRec
GetMinMaxArray CGSortLibArr(), start&, finish&, RSMMrec
IF CGSortLibArr(RSMMrec.min) = CGSortLibArr(RSMMrec.max) THEN EXIT SUB '* no div0 bombs
delta# = CGSortLibArr(RSMMrec.max) - CGSortLibArr(RSMMrec.min)
DIM pow2 AS _UNSIGNED _INTEGER64
DIM NtmpN AS _UNSIGNED _INTEGER64
DIM Int64MaxShift AS _INTEGER64: Int64MaxShift = 2 ^ 64
REDIM ct&(-1 TO 1)
REDIM RadixCGSortLibArr(0 TO 1, finish& - start&) AS DOUBLE
SELECT CASE order&
CASE 1
pow2 = Int64MaxShift
bits& = LEN(Int64MaxShift) * 8
DO UNTIL bits& < 0
FOR i& = start& TO finish&
NtmpN = Int64MaxShift * (CGSortLibArr(i&) - CGSortLibArr(RSMMrec.min)) / (delta#)
IF NtmpN AND pow2 THEN
tmpradix% = 1
ELSE
tmpradix% = 0
END IF
RadixCGSortLibArr(tmpradix%, ct&(tmpradix%)) = CGSortLibArr(i&)
ct&(tmpradix%) = ct&(tmpradix%) + 1
NEXT
c& = start&
FOR i& = 0 TO 1
FOR j& = 0 TO ct&(i&) - 1
CGSortLibArr(c&) = RadixCGSortLibArr(i&, j&)
c& = c& + 1
NEXT
ct&(i&) = 0
NEXT
pow2 = pow2 / 2
bits& = bits& - 1
LOOP
CASE ELSE
pow2 = 1
FOR bits& = 0 TO 63
FOR i& = start& TO finish&
NtmpN = Int64MaxShift * (CGSortLibArr(i&) - CGSortLibArr(RSMMrec.min)) / (delta#)
IF NtmpN AND pow2 THEN
tmpradix% = 1
ELSE
tmpradix% = 0
END IF
RadixCGSortLibArr(tmpradix%, ct&(tmpradix%)) = CGSortLibArr(i&)
ct&(tmpradix%) = ct&(tmpradix%) + 1
NEXT
c& = start&
FOR i& = 0 TO 1
FOR j& = 0 TO ct&(i&) - 1
CGSortLibArr(c&) = RadixCGSortLibArr(i&, j&)
c& = c& + 1
NEXT
ct&(i&) = 0
NEXT
pow2 = pow2 * 2
NEXT
END SELECT
ERASE RadixCGSortLibArr, ct&
END IF
END SUB
SUB ArrayIsInteger (CGSortLibArr() AS DOUBLE, start&, finish&, errorindex&, IsInt&)
IsInt& = 1
errorindex& = start&
FOR IsIntegerS& = start& TO finish&
IF CGSortLibArr(IsIntegerS&) MOD 1 THEN
errorindex& = IsIntegerS&
IsInt& = 0
EXIT FUNCTION
END IF
NEXT
END FUNCTION
SUB MergeSort (CGSortLibArr() AS DOUBLE, start&, finish&, order&)
SELECT CASE finish& - start&
CASE IS > 31
middle& = start& + (finish& - start&) \ 2
MergeSort CGSortLibArr(), start&, middle&, order&
MergeSort CGSortLibArr(), middle& + 1, finish&, order&
'IF order& = 1 THEN
EfficientMerge CGSortLibArr(), start&, finish&, order&
'ELSE
' MergeRoutine CGSortLibArr(), start&, finish&, order&
'END IF
CASE IS > 0
InsertionSort CGSortLibArr(), start&, finish&, order&
END SELECT
END SUB
SUB EfficientMerge (right() AS DOUBLE, start&, finish&, order&)
half& = start& + (finish& - start&) \ 2
REDIM left(start& TO half&) AS DOUBLE '* hold the first half of the array in left() -- must be the same type as right()
FOR LoadLeft& = start& TO half&
left(LoadLeft&) = right(LoadLeft&)
NEXT
SELECT CASE order&
CASE 1
i& = start&
j& = half& + 1
insert& = start&
DO
IF i& > half& THEN '* left() exhausted
IF j& > finish& THEN '* right() exhausted
EXIT DO
ELSE
'* stuff remains in right to be inserted, so flush right()
WHILE j& <= finish&
right(insert&) = right(j&)
j& = j& + 1
insert& = insert& + 1
WEND
EXIT DO
'* and exit
END IF
ELSE
IF j& > finish& THEN
WHILE i& < LoadLeft&
right(insert&) = left(i&)
i& = i& + 1
insert& = insert& + 1
WEND
EXIT DO
ELSE
IF right(j&) < left(i&) THEN
right(insert&) = right(j&)
j& = j& + 1
ELSE
right(insert&) = left(i&)
i& = i& + 1
END IF
insert& = insert& + 1
END IF
END IF
LOOP
CASE ELSE
i& = start&
j& = half& + 1
insert& = start&
DO
IF i& > half& THEN '* left() exhausted
IF j& > finish& THEN '* right() exhausted
EXIT DO
ELSE
'* stuff remains in right to be inserted, so flush right()
WHILE j& <= finish&
right(insert&) = right(j&)
j& = j& + 1
insert& = insert& + 1
WEND
EXIT DO
'* and exit
END IF
ELSE
IF j& > finish& THEN
WHILE i& < LoadLeft&
right(insert&) = left(i&)
i& = i& + 1
insert& = insert& + 1
WEND
EXIT DO
ELSE
IF right(j&) > left(i&) THEN
right(insert&) = right(j&)
j& = j& + 1
ELSE
right(insert&) = left(i&)
i& = i& + 1
END IF
insert& = insert& + 1
END IF
END IF
LOOP
END SELECT
ERASE left
END SUB
SUB GetMinMaxArray (CGSortLibArr() AS DOUBLE, Start&, Finish&, GetMinMaxArray_minmax AS MinMaxRec)
DIM GetGetMinMaxArray_minmaxArray_i AS LONG
DIM GetMinMaxArray_n AS LONG
DIM GetMinMaxArray_TT AS LONG
DIM GetMinMaxArray_NMod2 AS INTEGER
'* this is a workaround for the irritating malfunction
'* of MOD using larger numbers and small divisors
GetMinMaxArray_n = Finish& - Start&
GetMinMaxArray_TT = GetMinMaxArray_n MOD 10000
GetMinMaxArray_NMod2 = GetMinMaxArray_n - 10000 * ((GetMinMaxArray_n - GetMinMaxArray_TT) / 10000)
IF (GetMinMaxArray_NMod2 MOD 2) THEN
GetMinMaxArray_minmax.min = Start&
GetMinMaxArray_minmax.max = Start&
GetGetMinMaxArray_minmaxArray_i = Start& + 1
ELSE
IF CGSortLibArr(Start&) > CGSortLibArr(Finish&) THEN
GetMinMaxArray_minmax.max = Start&
GetMinMaxArray_minmax.min = Finish&
ELSE
GetMinMaxArray_minmax.min = Finish&
GetMinMaxArray_minmax.max = Start&
END IF
GetGetMinMaxArray_minmaxArray_i = Start& + 2
END IF
WHILE GetGetMinMaxArray_minmaxArray_i < Finish&
IF CGSortLibArr(GetGetMinMaxArray_minmaxArray_i) > CGSortLibArr(GetGetMinMaxArray_minmaxArray_i + 1) THEN
IF CGSortLibArr(GetGetMinMaxArray_minmaxArray_i) > CGSortLibArr(GetMinMaxArray_minmax.max) THEN
GetMinMaxArray_minmax.max = GetGetMinMaxArray_minmaxArray_i
END IF
IF CGSortLibArr(GetGetMinMaxArray_minmaxArray_i + 1) < CGSortLibArr(GetMinMaxArray_minmax.min) THEN
GetMinMaxArray_minmax.min = GetGetMinMaxArray_minmaxArray_i + 1
END IF
ELSE
IF CGSortLibArr(GetGetMinMaxArray_minmaxArray_i + 1) > CGSortLibArr(GetMinMaxArray_minmax.max) THEN
GetMinMaxArray_minmax.max = GetGetMinMaxArray_minmaxArray_i + 1
END IF
IF CGSortLibArr(GetGetMinMaxArray_minmaxArray_i) < CGSortLibArr(GetMinMaxArray_minmax.min) THEN
GetMinMaxArray_minmax.min = GetGetMinMaxArray_minmaxArray_i
END IF
END IF
GetGetMinMaxArray_minmaxArray_i = GetGetMinMaxArray_minmaxArray_i + 2
WEND
END SUB
SUB InsertionSort (CGSortLibArr() AS DOUBLE, start AS LONG, finish AS LONG, order&)
DIM InSort_Local_ArrayTemp AS DOUBLE
DIM InSort_Local_i AS LONG
DIM InSort_Local_j AS LONG
SELECT CASE order&
CASE 1
FOR InSort_Local_i = start + 1 TO finish
InSort_Local_ArrayTemp = CGSortLibArr(InSort_Local_i)
InSort_Local_j = InSort_Local_i - 1
DO UNTIL InSort_Local_j < start
IF (InSort_Local_ArrayTemp < CGSortLibArr(InSort_Local_j)) THEN
CGSortLibArr(InSort_Local_j + 1) = CGSortLibArr(InSort_Local_j)
InSort_Local_j = InSort_Local_j - 1
ELSE
EXIT DO
END IF
LOOP
CGSortLibArr(InSort_Local_j + 1) = InSort_Local_ArrayTemp
NEXT
CASE ELSE
FOR InSort_Local_i = start + 1 TO finish
InSort_Local_ArrayTemp = CGSortLibArr(InSort_Local_i)
InSort_Local_j = InSort_Local_i - 1
DO UNTIL InSort_Local_j < start
IF (InSort_Local_ArrayTemp > CGSortLibArr(InSort_Local_j)) THEN
CGSortLibArr(InSort_Local_j + 1) = CGSortLibArr(InSort_Local_j)
InSort_Local_j = InSort_Local_j - 1
ELSE
EXIT DO
END IF
LOOP
CGSortLibArr(InSort_Local_j + 1) = InSort_Local_ArrayTemp
NEXT
END SELECT
END SUB </lang>
Racket
<lang Racket>
- lang Racket
(define (radix-sort l r)
(define queues (for/vector #:length r ([_ r]) (make-queue)))
(let loop ([l l] [R 1])
(define all-zero? #t)
(for ([x (in-list l)])
(define x/R (quotient x R))
(enqueue! (vector-ref queues (modulo x/R r)) x)
(unless (zero? x/R) (set! all-zero? #f)))
(if all-zero? l
(loop (let q-loop ([i 0])
(define q (vector-ref queues i))
(let dq-loop ()
(if (queue-empty? q)
(if (< i (sub1 r)) (q-loop (add1 i)) '())
(cons (dequeue! q) (dq-loop)))))
(* R r)))))
(for/and ([i 10000]) ; run some tests on random lists with a random radix
(define (make-random-list)
(for/list ([i (+ 10 (random 10))]) (random 100000)))
(define (sorted? l)
(match l [(list) #t] [(list x) #t]
[(list x y more ...) (and (<= x y) (sorted? (cons y more)))]))
(sorted? (radix-sort (make-random-list) (+ 2 (random 98)))))
- => #t, so all passed
</lang>
Raku
(formerly Perl 6) A base-10 radix sort, done on the string representation of the integers. Signs are handled by in-place reversal of the '-' bucket on the last iteration. (The sort in there is not cheating; it only makes sure we process the buckets in the right order, since classify might return the buckets in random order. It might be more efficient to create our own ordered buckets, but this is succinct.) <lang perl6>sub radsort (@ints) {
my $maxlen = max @ints».chars;
my @list = @ints».fmt("\%0{$maxlen}d");
for reverse ^$maxlen -> $r {
my @buckets = @list.classify( *.substr($r,1) ).sort: *.key;
@buckets[0].value = @buckets[0].value.reverse.List
if !$r and @buckets[0].key eq '-';
@list = flat map *.value.values, @buckets;
}
@list».Int;
}
.say for radsort (-2_000 .. 2_000).roll(20);</lang>
- Output:
-1585 -1427 -1228 -1067 -945 -657 -643 -232 -179 -28 37 411 488 509 716 724 1504 1801 1864 1939
REXX
This REXX version also works with malformed integers. 7, 007, +7, .7e1, 7.0 are all treated as equal. <lang rexx>/*REXX program performs a radix sort on an integer array (can be negative/zero/positive)*/ call gen /*call subroutine to generate numbers. */ call radSort n /*invoke the radix sort subroutine. */ call show /*display the elements in the @ array*/ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ gen: ILF= 0 2 3 4 5 5 7. 6 6 7 11 7 13 9 8 8 17 8 19 9 10 13 23 9 10 15 ,
9 11 29 10 31 10 14 19 12 10 37 21 16 11 41 12 43 15 11 25 47 11 14 12 20 17 ,
53 11 16 13 22 31 59 12 61 33 13 12 18 16 67 21 26 14 71 12 73 39 13 23 18 18 ,
79 13 12 43 83 14 22 45 32 17 89 13 20 27 34 49 24 13 97 16 17 14 101 ,
'22 103 19 15 55 107 13 109 18 40 15 113 -42'
/*excluding -42, abbreviated above list is called the integer log function*/
n= words(ILF) /* I────── L── F───────*/
w= 0; do m=1 for n; _= word(ILF,m) +0; @.m= _; w= max(w, length(_) )
end /*m*/; return /*W: is the maximum width ↑ of numbers*/
/*──────────────────────────────────────────────────────────────────────────────────────*/ radSort: procedure expose @. w; parse arg size; mote= c2d(' '); #= 1; !.#._n= size !.#._b= 1 !.#._i= 1; do i=1 for size; y=@.i; @.i= right(abs(y), w, 0); if y<0 then @.i= '-'@.i
end /*i*/ /* [↑] negative case.*/
do while #\==0; ctr.= 0; L= 'ffff'x; low= !.#._b; n= !.#._n; $= !.#._i; H=
#= #-1 /* [↑] is the radix. */
do j=low for n; parse var @.j =($) _ +1; ctr._= ctr._ + 1
if ctr._==1 & _\== then do; if _<<L then L=_; if _>>H then H=_
end /* ↑↑ */
end /*j*/ /* └┴─────◄─── << is a strict comparison.*/
_= /* ┌──◄─── >> " " " " */
if L>>H then iterate /*◄─────┘ */
if L==H & ctr._==0 then do; #= #+1; !.#._b= low; !.#._n= n; !.#._i= $+1; iterate
end
L= c2d(L); H= c2d(H); ?= ctr._ + low; top._= ?; ts= mote
max= L
do k=L to H; _= d2c(k, 1); c= ctr._ /* [↓] swap 2 item radices.*/
if c>ts then parse value c k with ts max; ?= ?+c; top._= ?
end /*k*/
piv= low /*set PIVot to the low part of the sort*/
do while piv<low+n
it= @.piv
do forever; parse var it =($) _ +1; c= top._ -1
if piv>=c then leave; top._= c; ?= @.c; @.c= it; it= ?
end /*forever*/
top._= piv; @.piv= it; piv= piv + ctr._
end /*while piv<low+n */
i= max
do until i==max; _= d2c(i, 1); i= i+1; if i>H then i= L; d= ctr._
if d<=mote then do; if d<2 then iterate; b= top._
do k=b+1 for d-1; q= @.k
do j=k-1 by -1 to b while q<<@.j; jp= j+1; @.jp= @.j
end /*j*/
jp= j+1; @.jp= q
end /*k*/
iterate
end
#= #+1; !.#._b= top._; !.#._n= d; !.#._i= $ + 1
end /*until i==max*/
end /*while #\==0 */
- = 0 /* [↓↓↓] handle neg. and pos. arrays. */
do i=size by -1 for size; if @.i>=0 then iterate; #= #+1; @@.#= @.i
end /*i*/
do j=1 for size; if @.j>=0 then do; #= #+1; @@.#= @.j; end; @.j= @@.j+0
end /*j*/ /* [↑↑↑] combine 2 lists into 1 list. */
return /*──────────────────────────────────────────────────────────────────────────────────────*/ show: do j=1 for n; say 'item' right(j, w) "after the radix sort:" right(@.j, w)
end /*j*/; return /* [↑] display sorted items ───► term.*/</lang>
- output (with the middle section elided.)
(Output is shown at 3/4 size.)
item 1 after the radix sort: -42 item 2 after the radix sort: 0 item 3 after the radix sort: 2 item 4 after the radix sort: 3 item 5 after the radix sort: 4 item 6 after the radix sort: 5 item 7 after the radix sort: 5 item 8 after the radix sort: 6 item 9 after the radix sort: 6 item 10 after the radix sort: 7 item 11 after the radix sort: 7 item 12 after the radix sort: 7 item 13 after the radix sort: 8 . . . (middle section elided.) . . . item 92 after the radix sort: 40 item 93 after the radix sort: 41 item 94 after the radix sort: 43 item 95 after the radix sort: 43 item 96 after the radix sort: 45 item 97 after the radix sort: 47 item 98 after the radix sort: 49 item 99 after the radix sort: 53 item 100 after the radix sort: 55 item 101 after the radix sort: 59 item 102 after the radix sort: 61 item 103 after the radix sort: 67 item 104 after the radix sort: 71 item 105 after the radix sort: 73 item 106 after the radix sort: 79 item 107 after the radix sort: 83 item 108 after the radix sort: 89 item 109 after the radix sort: 97 item 110 after the radix sort: 101 item 111 after the radix sort: 103 item 112 after the radix sort: 107 item 113 after the radix sort: 109 item 114 after the radix sort: 113
Ruby
Negative number handling courtesy the Tcl solution. <lang ruby>class Array
def radix_sort(base=10)
ary = dup
rounds = (Math.log(ary.minmax.map(&:abs).max)/Math.log(base)).floor + 1
rounds.times do |i|
buckets = Array.new(2*base){[]}
base_i = base**i
ary.each do |n|
digit = (n/base_i) % base
digit += base if 0<=n
buckets[digit] << n
end
ary = buckets.flatten
p [i, ary] if $DEBUG
end
ary
end
def radix_sort!(base=10)
replace radix_sort(base)
end
end
p [1, 3, 8, 9, 0, 0, 8, 7, 1, 6].radix_sort p [170, 45, 75, 90, 2, 24, 802, 66].radix_sort p [170, 45, 75, 90, 2, 24, -802, -66].radix_sort p [100000, -10000, 400, 23, 10000].radix_sort</lang> running with $DEBUG on produces:
[0, [0, 0, 1, 1, 3, 6, 7, 8, 8, 9]] [0, 0, 1, 1, 3, 6, 7, 8, 8, 9] [0, [170, 90, 2, 802, 24, 45, 75, 66]] [1, [2, 802, 24, 45, 66, 170, 75, 90]] [2, [2, 24, 45, 66, 75, 90, 170, 802]] [2, 24, 45, 66, 75, 90, 170, 802] [0, [-66, -802, 170, 90, 2, 24, 45, 75]] [1, [-66, -802, 2, 24, 45, 170, 75, 90]] [2, [-802, -66, 2, 24, 45, 75, 90, 170]] [-802, -66, 2, 24, 45, 75, 90, 170] [0, [-10000, 100000, 400, 10000, 23]] [1, [-10000, 100000, 400, 10000, 23]] [2, [-10000, 100000, 10000, 23, 400]] [3, [-10000, 100000, 10000, 23, 400]] [4, [-10000, 100000, 23, 400, 10000]] [5, [-10000, 23, 400, 10000, 100000]] [-10000, 23, 400, 10000, 100000]
another version (After sorting at the absolute value, it makes a negative order reverse.) <lang ruby>class Array
def radix_sort(base=10)
ary = dup
m, max = 1, ary.minmax.map(&:abs).max
while m <= max
buckets = Array.new(base){[]}
ary.each {|n| buckets[(n.abs / m) % base] << n}
ary = buckets.flatten
m *= base
end
ary.partition{|n| n<0}.inject{|minus,plus| minus.reverse + plus}
end
end</lang>
Scala
<lang Scala>object RadixSort extends App {
def sort(toBeSort: Array[Int]): Array[Int] = { // Loop for every bit in the integers
var arr = toBeSort
for (shift <- Integer.SIZE - 1 until -1 by -1) { // The array to put the partially sorted array into
val tmp = new Array[Int](arr.length)
// The number of 0s
var j = 0
// Move the 0s to the new array, and the 1s to the old one
for (i <- arr.indices) // If there is a 1 in the bit we are testing, the number will be negative
// If this is the last bit, negative numbers are actually lower
if ((shift == 0) == (arr(i) << shift >= 0)) arr(i - j) = arr(i)
else {
tmp(j) = arr(i)
j += 1
}
// Copy over the 1s from the old array
arr.copyToArray(tmp, j, arr.length - j)
// And now the tmp array gets switched for another round of sorting
arr = tmp
}
arr
}
println(sort(Array(170, 45, 75, -90, -802, 24, 2, 66)).mkString(", "))
}</lang>
Sidef
<lang ruby>class Array {
method radix_sort(base=10) {
var arr = self.clone
var rounds = ([arr.minmax].map{.abs}.max.ilog(base) + 1)
for i in (0..rounds) {
var buckets = (2*base -> of {[]})
var base_i = base**i
for n in arr {
var digit = (n/base_i % base)
digit += base if (0 <= n)
buckets[digit].append(n)
}
arr = buckets.flat
}
return arr
}
}
for arr in [
[1, 3, 8, 9, 0, 0, 8, 7, 1, 6], [170, 45, 75, 90, 2, 24, 802, 66], [170, 45, 75, 90, 2, 24, -802, -66], [100000, -10000, 400, 23, 10000],
] {
say arr.radix_sort
}</lang>
- Output:
[0, 0, 1, 1, 3, 6, 7, 8, 8, 9] [2, 24, 45, 66, 75, 90, 170, 802] [-802, -66, 2, 24, 45, 75, 90, 170] [-10000, 23, 400, 10000, 100000]
Tailspin
<lang tailspin> templates radixsort@{base:}
sink bucketize
def value: $;
$ ~/ $@radixsort.digit -> #
<=0 ?($value <0..>)>
..|@radixsort.positives: $value;
<=0>
..|@radixsort.negatives(last): $value;
<>
def bucket: $ mod $base -> \(<?($value<0..>)> $ + 1 ! <=0> $base ! <> $ !\);
..|@radixsort.buckets($bucket): $value;
@radixsort.done: 0;
end bucketize
// Negatives get completed in wrong length-order, we need to collect by length and correct at the end
@: { done: 1, digit: 1, positives: [], negatives: [[]], buckets: [1..$base -> []]};
$... -> !bucketize
$@.done -> #
<=1>
[$@.negatives(last..1:-1)... ..., $@.positives...] !
<>
def previous: $@.buckets;
..|@: {done: 1, digit: $@.digit * $base, buckets:[1..$base -> []]};
..|@.negatives: [];
$previous... ... -> !bucketize
$@.done -> #
end radixsort
[170, 45, 75, 91, 90, 92, 802, 24, 2, 66] -> radixsort@{base:10} -> !OUT::write ' ' -> !OUT::write [-170, -45, -91, -90, -92, -802, -24, -2, -76] -> radixsort@{base:10} -> !OUT::write ' ' -> !OUT::write [170, 45, 75, -91, -90, -92, -802, 24, 2, 66] -> radixsort@{base:10} -> !OUT::write ' ' -> !OUT::write [170, 45, 75, -91, -90, -92, -802, 24, 2, 66] -> radixsort@{base:3} -> !OUT::write </lang>
- Output:
[2, 24, 45, 66, 75, 90, 91, 92, 170, 802] [-802, -170, -92, -91, -90, -76, -45, -24, -2] [-802, -92, -91, -90, 2, 24, 45, 66, 75, 170] [-802, -92, -91, -90, 2, 24, 45, 66, 75, 170]
Tcl
<lang tcl>package require Tcl 8.5 proc splitByRadix {lst base power} {
# create a list of empty lists to hold the split by digit
set out [lrepeat [expr {$base*2}] {}]
foreach item $lst {
# pulls the selected digit set digit [expr {($item / $base ** $power) % $base + $base * ($item >= 0)}] # append the number to the list selected by the digit lset out $digit [list {*}[lindex $out $digit] $item]
} return $out
}
- largest abs value element of a list
proc tcl::mathfunc::maxabs {lst} {
set max [abs [lindex $lst 0]]
for {set i 1} {$i < [llength $lst]} {incr i} {
set v [abs [lindex $lst $i]] if {$max < $v} {set max $v}
} return $max
}
proc radixSort {lst {base 10}} {
# there are as many passes as there are digits in the longest number
set passes [expr {int(log(maxabs($lst))/log($base) + 1)}]
# For each pass...
for {set pass 0} {$pass < $passes} {incr pass} {
# Split by radix, then merge back into the list set lst [concat {*}[splitByRadix $lst $base $pass]]
} return $lst
}</lang> Demonstrations: <lang tcl>puts [radixSort {1 3 8 9 0 0 8 7 1 6}] puts [radixSort {170 45 75 90 2 24 802 66}] puts [radixSort {170 45 75 90 2 24 -802 -66}]</lang> Output:
0 0 1 1 3 6 7 8 8 9 2 24 45 66 75 90 170 802 -802 -66 2 24 45 75 90 170
Wren
This is based on the approach used here which I've adjusted to deal with negative elements. <lang ecmascript>// counting sort of 'a' according to the digit represented by 'exp' var countSort = Fn.new { |a, exp|
var n = a.count
var output = [0] * n
var count = [0] * 10
for (i in 0...n) {
var t = (a[i]/exp).truncate % 10
count[t] = count[t] + 1
}
for (i in 1..9) count[i] = count[i] + count[i-1]
for (i in n-1..0) {
var t = (a[i]/exp).truncate % 10
output[count[t] - 1] = a[i]
count[t] = count[t] - 1
}
for (i in 0...n) a[i] = output[i]
}
// sorts 'a' in place var radixSort = Fn.new { |a|
// check for negative elements
var min = a.reduce { |m, i| (i < m) ? i : m }
// if there are any, increase all elements by -min
if (min < 0) (0...a.count).each { |i| a[i] = a[i] - min }
// now get the maximum to know number of digits
var max = a.reduce { |m, i| (i > m) ? i : m }
// do counting sort for each digit
var exp = 1
while ((max/exp).truncate > 0) {
countSort.call(a, exp)
exp = exp * 10
}
// if there were negative elements, reduce all elements by -min
if (min < 0) (0...a.count).each { |i| a[i] = a[i] + min }
}
var aa = [[4, 65, 2, -31, 0, 99, 2, 83, 782, 1], [170, 45, 75, 90, 2, 24, -802, -66]] for (a in aa) {
System.print("Unsorted: %(a)")
radixSort.call(a)
System.print("Sorted : %(a)\n")
}</lang>
- Output:
Unsorted: [4, 65, 2, -31, 0, 99, 2, 83, 782, 1] Sorted : [-31, 0, 1, 2, 2, 4, 65, 83, 99, 782] Unsorted: [170, 45, 75, 90, 2, 24, -802, -66] Sorted : [-802, -66, 2, 24, 45, 75, 90, 170]
zkl
In place int sort, fairly light on garbage creation. <lang zkl>fcn radixSort(ns){ // ints only, inplace, ns is mutable
b:=(0).pump(20,List,List().copy); // 20 [empty] buckets: -10..10
z:=ns.reduce(fcn(a,b){ a.abs().max(b.abs()) },0); // |max or min of input|
m:=1;
while(z){
ns.apply2('wrap(n){ b[(n/m)%10 +10].append(n) }); // sort on right digit
ns.clear(); b.pump(ns.extend); // slam buckets over src
b.apply("clear"); // reset buckets
m*=10; z/=10; // move sort digit left
}
ns
}</lang> <lang zkl>radixSort(T(170, 45, 75, 90, 802, 2, 24, 66)).println(); radixSort(T(170, 45, 75, -90, -802, 24, 2, 66)).println();</lang>
- Output:
L(2,24,45,66,75,90,170,802) L(-802,-90,2,24,45,66,75,170)