Excel VBA Quickest way to sort an array of numbers in descending order?

Question

What is the quickest way (in terms of computational time) to sort an array of numbers (1000-10000 numbers but could vary) in descending order? As far as I know the Excel build-in functions is not really efficient and in-memory sorting should be a lot faster than the Excel functions.

Note that I can not create anything on the spreadsheet, everything has to be stored and sorted in memory only.

Answer 1

You could use System.Collections.ArrayList:

Dim arr As Object
Dim cell As Range

Set arr = CreateObject("System.Collections.ArrayList")

' Initialise the ArrayList, for instance by taking values from a range:
For Each cell In Range("A1:F1")
    arr.Add cell.Value
Next

arr.Sort
' Optionally reverse the order
arr.Reverse

This uses Quick Sort.

Answer 2

Just so that people don't have to click the link that I just did, here is one of the fantastic examples from Siddharth's comment.

Option Explicit
Option Compare Text

' Omit plngLeft & plngRight; they are used internally during recursion
Public Sub QuickSort(ByRef pvarArray As Variant, Optional ByVal plngLeft As Long, Optional ByVal plngRight As Long)
    Dim lngFirst As Long
    Dim lngLast As Long
    Dim varMid As Variant
    Dim varSwap As Variant

    If plngRight = 0 Then
        plngLeft = LBound(pvarArray)
        plngRight = UBound(pvarArray)
    End If
    lngFirst = plngLeft
    lngLast = plngRight
    varMid = pvarArray((plngLeft + plngRight) \ 2)
    Do
        Do While pvarArray(lngFirst) < varMid And lngFirst < plngRight
            lngFirst = lngFirst + 1
        Loop
        Do While varMid < pvarArray(lngLast) And lngLast > plngLeft
            lngLast = lngLast - 1
        Loop
        If lngFirst <= lngLast Then
            varSwap = pvarArray(lngFirst)
            pvarArray(lngFirst) = pvarArray(lngLast)
            pvarArray(lngLast) = varSwap
            lngFirst = lngFirst + 1
            lngLast = lngLast - 1
        End If
    Loop Until lngFirst > lngLast
    If plngLeft < lngLast Then QuickSort pvarArray, plngLeft, lngLast
    If lngFirst < plngRight Then QuickSort pvarArray, lngFirst, plngRight
End Sub