[转载]常用内部排序算法--用VB6实现

转自（http://www.cnblogs.com/IDqq/archive/2006/04/04/366688.html）

1 冒泡排序

冒泡排序虽然性能不高，但好歹是一种稳定的排序。在要求排序结果稳定，或者性能问题不很突出（比如给只含少量元素的小数组排序）的时候，用起来还是比较方便。下面给出一个较为通用的实现。

' 升序冒泡
 Private Sub Sort(ByRef ary As Variant)
     Dim i               As Long
     Dim j               As Long
     Dim vTmp            As Variant
 
     For i = 0 To UBound(ary) - 1
         For j = i + 1 To UBound(ary)
             If ary(i) > ary(j) Then
                vTmp = ary(i)
                ary(i) = ary(j)
                ary(j) = vTmp
            End If
        Next
    Next
End Sub

2 快速排序

快排可以说是应用最为广泛的一种排序了。快排的平均排序性能最好，但不是稳定的排序。

' 升序快排
 Private Sub QuickSort(ByRef ary As Variant)
     Call QSort(ary, 0, UBound(ary))
 End Sub
 
 ' 子函数：对子数组递归排序
 Private Sub QSort(ByRef ary As Variant, ByVal lLow As Long, ByVal lHigh As Long)
     Dim lPivot          As Long
 
    If lLow < lHigh Then
        lPivot = Part(ary, lLow, lHigh)
        Call QSort(ary, lLow, lPivot - 1)
        Call QSort(ary, lPivot + 1, lHigh)
    End If
End Sub

' 子函数：选定ary(lLow)为枢轴，把数组分成比枢轴大/小的两部分
Private Function Part(ByRef ary As Variant, ByVal lLow As Long, ByVal lHigh As Long) As Long
    Dim vPivot          As Variant

    vPivot = ary(lLow)
    Do While lLow < lHigh
        Do While lLow < lHigh And ary(lHigh) >= vPivot
            lHigh = lHigh - 1
        Loop
        If lLow = lHigh Then Exit Do
        ary(lLow) = ary(lHigh)
        Do While lLow < lHigh And ary(lLow) <= vPivot
            lLow = lLow + 1
        Loop
        If lLow = lHigh Then Exit Do
        ary(lHigh) = ary(lLow)
    Loop
    ary(lLow) = vPivot
    Part = lLow
End Function

3 用法示例

Dim ary As Variant
Dim byt As Byte()
ary = Array(1, 3, 2, 5, 12, 8, 7, 9)
Sort ary
byt = StrConv("AZCDI", vbFromUnicode)
Sort byt
ary = Array(8, 1, 3, 2, 5, 12, 7, 9)
QuickSort ary