|
#2
QQ670653022015-05-05 23:09
Private Function Bs(ByVal List() As Integer, ByVal N As Integer) As Integer
Dim Low As Integer, Up As Integer, Midi As Integer Low = LBound(List) Up = UBound(List) Do While Low <= Up Midi = (Low + Up) / 2 If List(Midi) = N Then Bs = Midi Exit Do ElseIf List(Midi) > N Then Up = Midi - 1 ElseIf List(Midi) < N Then Low = Midi + 1 End If Loop If Low > Up Then Bs = -1 End Function Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click Dim A As Int32(), b As Int32(), c As Boolean(), i As Int32 ReDim A(65000), b(66666), c(65000) Dim rAd As New System.Random Dim Stp As New Stopwatch Stp.Start() For i = 0 To A.Length - 1 A(i) = rAd.Next(0, 99999) Next For i = 0 To b.Length - 1 b(i) = rAd.Next(0, 99999) Next Array.Sort(A) '排序与否无所谓，重复与否不影响 Array.Sort(b) For i = 0 To A.Length - 1 If Bs(A, b(i)) >= 0 Then c(i) = True Else c(i) = False End If Next Me.Text = "二分法测试" & (Stp.ElapsedMilliseconds) & "毫秒" End Sub 用二分法差不多80毫秒，基本上满足了 |
有两组随机生成的（0～99999）Int32数据A和B，将A按顺序判断在B中是否存在并记录在Boolean型的C中，我分别尝试了Array与List（Of T),在VS2010下以我的破电脑的速度Array大概需要4秒，而List（Of T）则要24秒，以下是我用Array和List(of T）的代码，请高手指点， 顺便问下有无秒杀的方法
'Array处理
Dim A As Int32(), b As Int32(), c As Boolean(), i As Int32
ReDim A(65000), b(66666), c(65000)
Dim rAd As New System.Random
Dim Stp As New Stopwatch
Stp.Start()
For i = 0 To A.Length - 1
A(i) = rAd.Next(0, 99999)
Next
For i = 0 To b.Length - 1
b(i) = rAd.Next(0, 99999)
Next
For i = 0 To A.Length - 1
If Array.IndexOf(b, A(i)) >= 0 Then
c(i) = True
Else
c(i) = False
End If
Next
Me.Text = "Array测试" & (Stp.ElapsedMilliseconds) & "毫秒"
'List(Of T)处理
Dim A As New List(Of Int32)
Dim B As New List(Of Int32)
Dim C As New List(Of Boolean)
Dim rAd As New System.Random
Dim Stp As New Stopwatch
Stp.Start()
For i As Int32 = 0 To 65000
A.Add(rAd.Next(0, 99999))
Next
For j As Int32 = 0 To 66666
B.Add(rAd.Next(0, 99999))
Next
For k As Int32 = 0 To A.Count - 1
If B.Contains(A.Item(k)) = True Then
C.Add(True)
Else
C.Add(False)
End If
Next
Me.Text = "list（of int32)测试" & (Stp.ElapsedMilliseconds) & "毫秒"