4.2 KiB
Script: measure-CountingSort.ps1
This PowerShell script measures the speed of the CountingSort algorithm. CountingSort is an algorithm for sorting a collection of objects according to keys that are small positive integers; that is, it is an integer sorting algorithm. It operates by counting the number of objects that possess distinct key values, and applying prefix sum on those counts to determine the positions of each key value in the output sequence. Its running time is linear in the number of items and the difference between the maximum key value and the minimum key value, so it is only suitable for direct use in situations where the variation in keys is not significantly greater than the number of items. It is often used as a subroutine in radix sort, another sorting algorithm, which can handle larger keys more efficiently.
Parameters
PS> ./measure-CountingSort.ps1 [[-numIntegers] <Int32>] [<CommonParameters>]
-numIntegers <Int32>
Specifies the number of integers to sort
Required? false
Position? 1
Default value 1000
Accept pipeline input? false
Accept wildcard characters? false
[<CommonParameters>]
This script supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction,
WarningVariable, OutBuffer, PipelineVariable, and OutVariable.
Example
PS> ./measure-CountingSort.ps1
🧭 0.045 sec to sort 1000 integers by CountingSort
Notes
Author: Markus Fleschutz | License: CC0
Related Links
https://github.com/fleschutz/PowerShell
Script Content
<#
.SYNOPSIS
Measures the speed of CountingSort
.DESCRIPTION
This PowerShell script measures the speed of the CountingSort algorithm.
CountingSort is an algorithm for sorting a collection of objects according to keys
that are small positive integers; that is, it is an integer sorting algorithm. It
operates by counting the number of objects that possess distinct key values, and
applying prefix sum on those counts to determine the positions of each key value in
the output sequence. Its running time is linear in the number of items and the difference
between the maximum key value and the minimum key value, so it is only suitable for direct
use in situations where the variation in keys is not significantly greater than the number
of items. It is often used as a subroutine in radix sort, another sorting algorithm, which
can handle larger keys more efficiently.
.PARAMETER numIntegers
Specifies the number of integers to sort
.EXAMPLE
PS> ./measure-CountingSort.ps1
🧭 0.045 sec to sort 1000 integers by CountingSort
.LINK
https://github.com/fleschutz/PowerShell
.NOTES
Author: Markus Fleschutz | License: CC0
#>
param([int]$numIntegers = 1000)
class CountingSort {
static Sort($targetList) {
$min = 0
$max = 0
for ($counter = 0; $counter -lt $targetList.Count; $counter++) {
if ($targetList[$counter] -lt $min) { $min = $targetList[$counter] }
if ($targetList[$counter] -gt $max) { $max = $targetList[$counter] }
}
$arrayBucket = New-Object int[] ($max - $min + 1)
for ($counter = 0; $counter -lt $targetList.Count; $counter++) {
$arrayBucket[$targetList[$counter]]++;
}
$lastPosition = 0
for ($counter = 0; $counter -lt $arrayBucket.Count ; $counter++) {
for ($innerCounter = 0; $innerCounter -lt $arrayBucket[$counter]; $innerCounter++) {
$targetList[$lastPosition++] = $counter
}
}
}
}
$list = (1..$numIntegers | foreach{Get-Random -minimum 1 -maximum $numIntegers})
$stopWatch = [system.diagnostics.stopwatch]::startNew()
[CountingSort]::Sort($list)
[float]$elapsed = $stopWatch.Elapsed.TotalSeconds
$elapsed3 = "{0:N3}" -f $elapsed # formatted to 3 decimal places
"🧭 $elapsed3 sec to sort $numIntegers integers by CountingSort"
exit 0 # success
(generated by convert-ps2md.ps1 using the comment-based help of measure-CountingSort.ps1 as of 03/27/2024 17:36:29)