排序算法

' min and max are the minimum and maximum indexes
' of the items that might still be out of order.
Sub BubbleSort (List() As Long, ByVal min As Integer, _
    ByVal max As Integer)
Dim last_swap As Integer
Dim i As Integer
Dim j As Integer
Dim tmp As Long

    ' Repeat until we are done.
    Do While min < max
        ' Bubble up.
        last_swap = min - 1
        ' For i = min + 1 To max
        i = min + 1
        Do While i <= max
            ' Find a bubble.
            If List(i - 1) > List(i) Then
                ' See where to drop the bubble.
                tmp = List(i - 1)
                j = i
                Do
                    List(j - 1) = List(j)
                    j = j + 1
                    If j > max Then Exit Do
                Loop While List(j) < tmp
                List(j - 1) = tmp
                last_swap = j - 1
                i = j + 1
            Else
                i = i + 1
            End If
        Loop
        ' Update max.
        max = last_swap - 1

        ' Bubble down.
        last_swap = max + 1
        ' For i = max - 1 To min Step -1
        i = max - 1
        Do While i >= min
            ' Find a bubble.
            If List(i + 1) < List(i) Then
                ' See where to drop the bubble.
                tmp = List(i + 1)
                j = i
                Do
                    List(j + 1) = List(j)
                    j = j - 1
                    If j < min Then Exit Do
                Loop While List(j) > tmp
                List(j + 1) = tmp
                last_swap = j + 1
                i = j - 1
            Else
                i = i - 1
            End If
        Loop
        ' Update min.
        min = last_swap + 1
    Loop
End Sub

Sub Selectionsort (List() As Long, min As Integer, _
    max As Integer)
Dim i As Integer
Dim j As Integer
Dim best_value As Long
Dim best_j As Integer

    For i = min To max - 1
        best_value = List(i)
        best_j = i
        For j = i + 1 To max
            If List(j) < best_value Then
                best_value = List(j)
                best_j = j
            End If
        Next j
        List(best_j) = List(i)
        List(i) = best_value
    Next i
End Sub

Sub Quicksort (List() As Long, min As Integer, max As Integer)
Dim med_value As Long
Dim hi As Integer
Dim lo As Integer
Dim i As Integer

    ' If the list has no more than 1 element, it's sorted.
    If min >= max Then Exit Sub

    ' Pick a dividing item.
    i = Int((max - min + 1) * Rnd + min)
    med_value = List(i)

    ' Swap it to the front so we can find it easily.
    List(i) = List(min)

    ' Move the items smaller than this into the left
    ' half of the list. Move the others into the right.
    lo = min
    hi = max
    Do
        ' Look down from hi for a value < med_value.
        Do While List(hi) >= med_value
            hi = hi - 1
            If hi <= lo Then Exit Do
        Loop
        If hi <= lo Then
            List(lo) = med_value
            Exit Do
        End If

        ' Swap the lo and hi values.
        List(lo) = List(hi)
        
        ' Look up from lo for a value >= med_value.
        lo = lo + 1
        Do While List(lo) < med_value
            lo = lo + 1
            If lo >= hi Then Exit Do
        Loop
        If lo >= hi Then
            lo = hi
            List(hi) = med_value
            Exit Do
        End If

        ' Swap the lo and hi values.
        List(hi) = List(lo)
    Loop

    ' Sort the two sublists
    Quicksort List(), min, lo - 1
    Quicksort List(), lo + 1, max
End Sub

Sub Countingsort (List() As Long, sorted_list() As Long, _
    min As Integer, max As Integer, min_value As Long, _
    max_value As Long)
Dim counts() As Integer
Dim i As Integer
Dim this_count As Integer
Dim next_offset As Integer

    ' Create the Counts array.
    ReDim counts(min_value To max_value)

    ' Count the items.
    For i = min To max
        counts(List(i)) = counts(List(i)) + 1
    Next i

    ' Convert the counts into offsets.
    next_offset = min
    For i = min_value To max_value
        this_count = counts(i)
        counts(i) = next_offset
        next_offset = next_offset + this_count
    Next i

    ' Place the items in the sorted array.
    For i = min To max
        sorted_list(counts(List(i))) = List(i)
        counts(List(i)) = counts(List(i)) + 1
    Next i
End Sub