mirror of
https://github.com/fleschutz/PowerShell.git
synced 2024-11-22 07:53:21 +01:00
60 lines
2.4 KiB
PowerShell
Executable File
60 lines
2.4 KiB
PowerShell
Executable File
<#
|
|
.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
|