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60 lines
2.4 KiB
PowerShell
Executable File
60 lines
2.4 KiB
PowerShell
Executable File
<#
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.SYNOPSIS
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Measures the speed of CountingSort
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.DESCRIPTION
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This PowerShell script measures the speed of the CountingSort algorithm.
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CountingSort is an algorithm for sorting a collection of objects according to keys
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that are small positive integers; that is, it is an integer sorting algorithm. It
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operates by counting the number of objects that possess distinct key values, and
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applying prefix sum on those counts to determine the positions of each key value in
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the output sequence. Its running time is linear in the number of items and the difference
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between the maximum key value and the minimum key value, so it is only suitable for direct
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use in situations where the variation in keys is not significantly greater than the number
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of items. It is often used as a subroutine in radix sort, another sorting algorithm, which
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can handle larger keys more efficiently.
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.PARAMETER numIntegers
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Specifies the number of integers to sort
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.EXAMPLE
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PS> ./measure-CountingSort.ps1
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🧭 0.045 sec to sort 1000 integers by CountingSort
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.LINK
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https://github.com/fleschutz/PowerShell
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.NOTES
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Author: Markus Fleschutz | License: CC0
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#>
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param([int]$numIntegers = 1000)
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class CountingSort {
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static Sort($targetList) {
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$min = 0
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$max = 0
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for ($counter = 0; $counter -lt $targetList.Count; $counter++) {
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if ($targetList[$counter] -lt $min) { $min = $targetList[$counter] }
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if ($targetList[$counter] -gt $max) { $max = $targetList[$counter] }
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}
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$arrayBucket = New-Object int[] ($max - $min + 1)
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for ($counter = 0; $counter -lt $targetList.Count; $counter++) {
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$arrayBucket[$targetList[$counter]]++;
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}
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$lastPosition = 0
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for ($counter = 0; $counter -lt $arrayBucket.Count ; $counter++) {
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for ($innerCounter = 0; $innerCounter -lt $arrayBucket[$counter]; $innerCounter++) {
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$targetList[$lastPosition++] = $counter
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}
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}
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}
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}
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$list = (1..$numIntegers | foreach{Get-Random -minimum 1 -maximum $numIntegers})
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$stopWatch = [system.diagnostics.stopwatch]::startNew()
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[CountingSort]::Sort($list)
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[float]$elapsed = $stopWatch.Elapsed.TotalSeconds
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$elapsed3 = "{0:N3}" -f $elapsed # formatted to 3 decimal places
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"🧭 $elapsed3 sec to sort $numIntegers integers by CountingSort"
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exit 0 # success
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