'ShellsortIndex - Philben - v1.0 - 03/2012
'Utilisable pour des tailles de tableau jusqu'à 10 000 000
'Les valeurs des gaps au-dessus de 1750 sont extrapolées et ne sont certainement pas les plus efficaces !
'Si le type de tableau est Integer, modifier :
'  - ByRef a() As Long     en ByRef a() As Integer
'  - Dim ref As Long       en Dim ref As Integer
Public Function ShellSortIndex(ByRef a() As Long, ByRef Idx() As Long, ByVal lowerBound As Long, ByVal upperBound As Long)
   Dim ref As Long
   Dim h As Long, i As Long, j As Long, k As Long, l As Long, m As Long, n As Long, refIdx As Long, g As Variant
 
   ReDim Idx(lowerBound To upperBound)
   For i = lowerBound To upperBound: Idx(i) = i: Next i
 
   g = Array(1, 4, 10, 23, 57, 132, 301, 701, 1750, 4376, 10941, 27353, 68383, 170958, 427396, 1068491, 2671228)
   n = upperBound - lowerBound + 1
 
   l = LBound(g)
   If n < g(UBound(g)) Then
      k = l
      While g(k + 1) < n: k = k + 1: Wend
   Else
      k = UBound(g)
   End If
 
   While k >= l
      h = g(k)
      m = lowerBound + h
      For i = m To upperBound
         ref = a(Idx(i))
         refIdx = Idx(i)
         j = i
         Do While ref < a(Idx(j - h))   '< pour un tri croissant, sinon >
           Idx(j) = Idx(j - h)
            j = j - h
            If j < m Then Exit Do
         Loop
         Idx(j) = refIdx
      Next i
      k = k - 1
   Wend
End Function

   For i = LBound(Idx) To UBound(Idx)
      Debug.Print a(Idx(i))
   Next i