利用集合进行数组的排序

笔者在学习VB中发现利用集合可以进行排序，优化后比冒泡法快得多。下面是完整的函数代码，演示了如何进行数组的升序或降序排列。

Option Explicit
Dim X(100) As Double
Dim y(100) As String
Private Sub Command1_Click() '演示数字排序
Dim a(100) As Double, z(100) As String, i As Long
For i = 0 To 100
a(i) = X(i) '复制数组
z(i) = CStr(X(i)) '转化为字符串数组
Next
MsgBox Join(z, ","), 64, "原始数组" '显示原始顺序

NUMBERSORT X, "up"
For i = 0 To 100
z(i) = CStr(X(i)) '转化为字符串数组
Next
MsgBox Join(z, ","), 64, "按数字升序排序后数组" '显示排序结果

NUMBERSORT a, "down"
For i = 0 To 100
z(i) = CStr(a(i)) '转化为字符串数组
Next
MsgBox Join(z, ","), 64, "按数字降序排序后数组" '显示排序结果

End Sub
Sub NUMBERSORT(ByRef a() As Double, Optional sort As String = "up") '数字排序
Dim min As Long, max As Long, num As Long, first As Long, last As Long, temp As Long, all As New Collection, steps As Long
min = LBound(a)
max = UBound(a)
all.Add a(min)
steps = 1
For num = min + 1 To max
last = all.Count
If a(num) < CDbl(all(1)) Then all.Add a(num), BEFORE:=1: GoTo nextnum '加到第一项
If a(num) > CDbl(all(last)) Then all.Add a(num), AFTER:=last: GoTo nextnum '加到最后一项

first = 1
Do While last > first + 1 '利用DO循环减少循环次数
temp = (last + first) \ 2
If a(num) > CDbl(all(temp)) Then
first = temp
Else
last = temp
steps = steps + 1
End If
Loop
all.Add a(num), BEFORE:=last '加到指定的索引

nextnum:
steps = steps + 1
Next
For num = min To max
If sort = "UP" Or sort = "up" Then a(num) = CDbl(all(num - min + 1)): steps = steps + 1 '升序
If sort = "DOWN" Or sort = "down" Then a(num) = CDbl(all(max - num + 1)): steps = steps + 1 '降序
Next
MsgBox "本数组共经过 " & steps & "步实现" & IIf(sort = "UP" Or sort = "up", "升序", "降序") & "排序！", 64, "INFORMATION"
Set all = Nothing
End Sub

Sub STRINGSORT(ByRef a() As String, Optional sort As String = "UP") '字符串排序
Dim min As Long, max As Long, num As Long, first As Long, last As Long, temp As Long, all As New Collection, steps As Long
min = LBound(a)
max = UBound(a)
all.Add a(min)
steps = 1
For num = min + 1 To max

first = 1
last = all.Count
If a(num) < all(1) Then all.Add a(num), BEFORE:=1: GoTo nextnum '加到第一项
If a(num) > all(last) Then all.Add a(num), AFTER:=last: GoTo nextnum '加到最后一项

Do While last > first + 1 '利用DO循环减少循环次数
temp = (last + first) \ 2
If a(num) > all(temp) Then
first = temp
Else
last = temp
steps = steps + 1
End If
Loop
all.Add a(num), BEFORE:=last '加到指定的索引

nextnum:
steps = steps + 1
Next
For num = min To max
If sort = "UP" Or sort = "up" Then a(num) = all(num - min + 1): steps = steps + 1 '升序
If sort = "DOWN" Or sort = "down" Then a(num) = all(max - num + 1): steps = steps + 1 '降序
Next
MsgBox "本数组共经过 " & steps & "步实现" & IIf(sort = "UP" Or sort = "up", "升序", "降序") & "排序！", 64, "INFORMATION"
Set all = Nothing
End Sub

Private Sub Command2_Click() '演示字符串排序
Dim z(100) As String, i As Long '复制数组
For i = 0 To 100
z(i) = y(i)
Next

MsgBox Join(y, ","), 64, "原始数组" '显示原始顺序

STRINGSORT y, "UP"
MsgBox Join(y, ","), 64, "按字符串升序排序后数组" '显示排序结果

STRINGSORT z, "DOWN"
MsgBox Join(z, ","), 64, "按字符串降序排序后数组" '显示排序结果
End Sub

Private Sub Command3_Click() ' 排序计时
Dim a(3000) As String, i As Long, starttime As Long, endtime As Long
For i = 0 To 3000
a(i) = Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) '生成随机6字符的字符串
Next
starttime = Timer '计时开始
STRINGSORT a
endtime = Timer '计时结束
MsgBox "排序共耗时 " & endtime - starttime & " 秒！"
End Sub

Private Sub Form_Load()
Randomize
Dim i As Long
For i = 0 To 100
X(i) = Format(Rnd * 1000, "0.00")
y(i) = Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65) & Chr(Int(Rnd * 26) + 65)
Next
End Sub