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How to order array in lexicographical order with mapped file vb.net


This is kinda complicated for me to understand

    Dim test() As Byte = New Byte() {50, 40, 30, 10, 10}
    Dim answer() As UInteger = SortLexicoGraphicallyArrayMappedFile(test)

The answer is the each Rotation sorted from lowest array value to highest array value.

Rotation 0 = 50, 40, 30, 10, 10
Rotation 1 = 10, 50, 40, 30, 10
Rotation 2 = 10, 10, 50, 40, 30
Rotation 3 = 30, 10, 10, 50, 40
Rotation 4 = 40, 30, 10, 10, 50

When I sort this array above by hand I should get

Rotation 2 = 10, 10, 50, 40, 30
Rotation 1 = 10, 50, 40, 30, 10
Rotation 3 = 30, 10, 10, 50, 40
Rotation 4 = 40, 30, 10, 10, 50
Rotation 0 = 50, 40, 30, 10, 10

So the answer should be 2, 1, 3, 4, 0

I get stuck in a infinite loop and I can't put my finger on it
My Previous question works because the data is always static here I try to move all the data around all over the place which is probably why it gets stuck I can't figure out a workaround around that.. i need to move all the data around to save cpu time later that's why I didn't pick the answer from the page below.

How to order array in lexicographical order vb.net

Here is my Code

Public Function GetRotation(Data As Byte(), rotation As UInteger) As Byte()
   'Rotation Left
    Dim rotationData As New List(Of Byte)

    Dim start As UInteger = Data.Length - rotation Mod Data.Length

    For i = 0 To Data.Length - 1
        rotationData.Add(Data((start + i) Mod (Data.Length)))
    Next

    Return rotationData.ToArray()
End Function

   Public Function SortLexicoGraphicallyArrayMappedFile(ByRef data As Byte()) As UInteger()
        Dim OrderedRotations As New List(Of UInteger)
        Dim rotatedData As Byte()
        Dim rotation As UInteger = 0


        Dim mmF As MemoryMappedFile
        mmF = MemoryMappedFile.CreateFromFile(My.Application.Info.DirectoryPath & "\outFile", FileMode.CreateNew, "test", CLng(data.LongLength * data.LongLength))
        Dim mmVA As MemoryMappedViewAccessor
        mmVA = mmF.CreateViewAccessor(0, data.LongLength * data.LongLength)

        Dim pos As Long = 0

        For rotation = 0 To data.Length - 1
            rotatedData = GetRotation(data, rotation)
            mmVA.WriteArray(Of Byte)(pos, rotatedData, 0, rotatedData.Length)
            pos += rotatedData.Length

        Next

        For rotation = 0 To data.Length - 1
            OrderedRotations.Add(rotation)
        Next

        Dim eachRotation As Integer = 0
        Dim data1() As Byte
        ReDim data1(data.Length - 1)
        Dim data2() As Byte
        ReDim data2(data.Length - 1)
        Dim index As Long
        For rotation = 0 To data.Length - 1
            Dim flag As Boolean
            Do
                flag = False
                For eachRotation = OrderedRotations.Count - 1 To 0 Step -1
                    mmVA.ReadArray(Of Byte)((OrderedRotations(rotation) * data.Length), data1, 0, data.Length)
                    If OrderedRotations(eachRotation) = OrderedRotations(rotation) Then Continue For
                    mmVA.ReadArray(Of Byte)((OrderedRotations(eachRotation) * data.Length), data2, 0, data.Length)

                    For index = 0 To data.Length - 1
                        If data1(index) > data2(index) Then
                            Exit For
                        ElseIf data1(index) < data2(index) Then
                            mmVA.WriteArray(Of Byte)((OrderedRotations(eachRotation) * data.Length), data1, 0, data1.Length)
                            mmVA.WriteArray(Of Byte)((OrderedRotations(rotation) * data.Length), data2, 0, data2.Length)

                            Dim tmpFirst As UInteger = OrderedRotations(rotation)
                            OrderedRotations(rotation) = OrderedRotations(eachRotation)
                            OrderedRotations(eachRotation) = tmpFirst
                            flag = True
                            Exit For
                        End If
                    Next
                Next
            Loop While flag
        Next

        Return OrderedRotations.ToArray()
    End Function

Solution

  • I don't know if this is right but I fixed it for you.

    Public Function SortLexicoGraphicallyArrayMappedFile(ByRef data As Byte()) As UInteger()
        Dim OrderedRotations As New List(Of UInteger)
        Dim rotatedData As Byte()
        Dim rotation As UInteger = 0
    
    
        Dim mmF As MemoryMappedFile
        mmF = MemoryMappedFile.CreateFromFile(My.Application.Info.DirectoryPath & "\outFile296", FileMode.CreateNew, "test", CLng(data.LongLength * data.LongLength))
        Dim mmVA As MemoryMappedViewAccessor
        mmVA = mmF.CreateViewAccessor(0, data.LongLength * data.LongLength)
    
        Dim pos As Long = 0
    
        For rotation = 0 To data.Length - 1
            rotatedData = GetRotation(data, rotation)
            mmVA.WriteArray(Of Byte)(pos, rotatedData, 0, rotatedData.Length)
            pos += rotatedData.Length
    
        Next
    
        For rotation = 0 To data.Length - 1
            OrderedRotations.Add(rotation)
        Next
    
        Dim eachRotation As Integer = 0
        Dim data1() As Byte
        ReDim data1(data.Length - 1)
        Dim data2() As Byte
        ReDim data2(data.Length - 1)
        Dim index As Long
        For rotation = 0 To data.Length - 1
            Dim flag As Boolean
            Do
                flag = False
                For eachRotation = OrderedRotations.Count - 1 To 0 Step -1
                    If rotation = eachRotation Then Exit For
                    mmVA.ReadArray(Of Byte)(rotation * data.Length, data1, 0, data.Length)
                    mmVA.ReadArray(Of Byte)((eachRotation * data.Length), data2, 0, data.Length)
    
                    For index = 0 To data.Length - 1
                        If data1(index) < data2(index) Then
                            Exit For
                        ElseIf data1(index) > data2(index) Then
                            mmVA.WriteArray(Of Byte)((eachRotation * data.Length), data1, 0, data1.Length)
                            mmVA.WriteArray(Of Byte)((rotation * data.Length), data2, 0, data2.Length)
    
                            Dim tmpFirst As UInteger = OrderedRotations(eachRotation)
                            OrderedRotations(eachRotation) = OrderedRotations(rotation)
                            OrderedRotations(rotation) = tmpFirst
                            flag = True
                            Exit For
                        End If
                    Next
                Next
            Loop While flag
        Next
    
        Return OrderedRotations.ToArray()
    End Function