vb.netb-tree
Nodes and Children structure mess, confusing
Here is a example how it should look (this is the same example as the code uses)
The code starts to screw up when changing from level 1 to level 2 a huge mess happens I don't understand it at all.
Here is the code
Public Class Node
Public label As Byte
Public visited As Boolean = False
Public level As Integer
Public Sub New(ByVal label As Byte, ByVal level As Integer)
Me.label = label
Me.level = level
End Sub
End Class
Public rootNodes As New List(Of Node)
Public nodes As New List(Of Node)
Dim adjMatrix As Byte(,)
Dim setDimensions As Boolean = False
Public Sub connectNode(ByVal start As Node, ByVal endd As Node)
'This method will be called to make connect two nodes
If setDimensions = False Then
ReDim Preserve adjMatrix(999 - 1, 999)
setDimensions = True
End If
Dim startIndex As Integer = nodes.IndexOf(start)
Dim endIndex As Integer = nodes.IndexOf(endd)
adjMatrix(startIndex, endIndex) = 1
adjMatrix(endIndex, startIndex) = 1
End Sub
Private Function getUnvisitedChildNode(ByVal n As Node) As Node
Dim index As Integer = nodes.IndexOf(n)
Dim j As Integer = 0
Do While j < nodes.Count
If adjMatrix(index, j) = 1 AndAlso nodes(j).visited = False Then
Return nodes(j)
End If
j += 1
Loop
Return Nothing
End Function
Private Sub clearNodes()
For Each n As Node In nodes
n.visited = False
Next
End Sub
Private Sub printNode(ByVal n As Node)
Debug.Print(n.label & " ")
End Sub
Public Enum Operation
LessThan = 0
GreaterThan = 1
End Enum
Public Function getPossibleNumbersForFirstByte(ByVal op As Operation, ByVal operationOf As Byte, ByVal numbersAlreadyUsed As List(Of Byte), ByVal totalSize As Long) As List(Of Byte)
Dim possibleNumbers As New List(Of Byte)
Dim tempNumber As Integer = -1
While True
If op = Operation.LessThan Then
tempNumber = IIf(tempNumber = -1, operationOf - 1, tempNumber - 1)
ElseIf op = Operation.GreaterThan Then
tempNumber = IIf(tempNumber = -1, operationOf + 1, tempNumber + 1)
End If
If tempNumber < 1 OrElse tempNumber > totalSize Then
Exit While
End If
If numbersAlreadyUsed Is Nothing OrElse numbersAlreadyUsed.Contains(tempNumber) = False Then
possibleNumbers.Add(tempNumber)
End If
End While
Return possibleNumbers
End Function
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
test()
End Sub
Sub test()
'Dim actualNumbers() As Byte = {5, 6, 1, 9, 7, 3, 8, 2, 4, 10}
Dim actualNumberList As New List(Of Byte)
actualNumberList.AddRange({5, 6, 1, 9, 7, 3, 8, 2, 4, 10})
Dim ListofGTLT() As Byte = {1, 0, 1, 0, 0, 1, 0, 1, 1}
Dim firstNumber As Byte = actualNumberList(0)
Dim possibleNumbersToUse As New List(Of Byte)
Dim numbersAlreadyUsed As New List(Of Byte)
For currentLevel = 0 To UBound(ListofGTLT)
'clear visited nodes.
clearNodes()
If currentLevel = 0 Then
'Generates Level 0 of all possible values in the first offset.
possibleNumbersToUse = getPossibleNumbersForFirstByte(ListofGTLT(currentLevel), firstNumber, Nothing, 10)
Dim n As Node
'Generates parent nodes of all possible values in the first offset.
For Each possibleNumber As Byte In possibleNumbersToUse
n = New Node(possibleNumber, 0)
rootNodes.Add(n)
nodes.Add(n)
Next
Else
Dim rootNode As Node
For Each rootNode In rootNodes
'Clear numbers already used.
numbersAlreadyUsed.Clear()
'Set already exists first value (known value).
numbersAlreadyUsed.Add(firstNumber)
If currentLevel = 1 Then
'Gets all the numbers which are possible connections.
possibleNumbersToUse = getPossibleNumbersForFirstByte(ListofGTLT(currentLevel), rootNode.label, numbersAlreadyUsed, 10)
Dim n As Node
'Setup connections with new nodes to root node.
For Each value As Byte In possibleNumbersToUse
n = New Node(value, 1)
nodes.Add(n)
'Debug.Print("[Connection]: " & rootNode.label & " = " & n.label)
connectNode(rootNode, n)
Next
Else
numbersAlreadyUsed.Add(rootNode.label)
Dim child = getUnvisitedChildNode(rootNode)
Do While child IsNot Nothing
Debug.Print("------------------------------------------")
Debug.Print("| Root = " & rootNode.label)
Debug.Print("| Child Level = " & child.level)
Debug.Print("| Child = " & child.label)
Debug.Print("------------------------------------------")
'Add to already existing values the child connection node.
If numbersAlreadyUsed.Contains(child.label) = False Then
If child.level = (currentLevel - 1) Then
'Gets next possible numbers which are possible connections.
possibleNumbersToUse = getPossibleNumbersForFirstByte(ListofGTLT(currentLevel), child.label, numbersAlreadyUsed, 10)
Dim n As Node
'Setup connections with new nodes to child node.
For Each value As Byte In possibleNumbersToUse
n = New Node(value, currentLevel)
nodes.Add(n)
connectNode(child, n)
Next
If child.level = 1 Then
'Finish all the level 1 childs for the current Root Node.
child.visited = True
child = getUnvisitedChildNode(rootNode)
Continue Do
Else
numbersAlreadyUsed.Add(child.label)
child.visited = True
child = getUnvisitedChildNode(child)
Continue Do
End If
Else
numbersAlreadyUsed.Add(child.label)
child.visited = True
child = getUnvisitedChildNode(child)
Continue Do
End If
Else
numbersAlreadyUsed.Add(child.label)
child.visited = True
child = getUnvisitedChildNode(child)
Continue Do
End If
Loop
End If
Next
End If
Next
End Sub
Solution
Instead of implementing your own class, using the TreeNode class, which is designed for this, makes your code much easier to understand, and has the added advantage of being native to the TreeView, which means all we have to do is add the base node and call ExpandAll and we have a graphical representation of our tree. Also what you want to do is well suited to a recursive routine. Here's a way that will build the tree structure. Whenever the child nodes are being added it skips any with a value already above it in the tree.
Private Sub btnAnswers_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
'Declare initial treenode with the value we want.
Dim Tree As New TreeNode("5")
'Declare the string of bits.
Dim input As String = "1001001001"
'Start the recursive routine
CalculateTreeNodes(Tree, input)
'Show the tree
TreeView1.Nodes.Add(Tree)
TreeView1.ExpandAll()h
End Sub
Private Sub CalculateTreeNodes(CurrentNode As TreeNode, directions As String)
If directions = "" Then Return
'Parse the text of the current node as byte
Dim value As Byte = Byte.Parse(CurrentNode.Text)
'Get the direction we want and truncate the string
Dim direction As Directions = CType([Enum].Parse(GetType(Directions), directions(0).ToString), Directions)
If directions.Length > 0 Then
directions = directions.Substring(1)
End If
'Get a list of the values of all the parent nodes above this one.
Dim Values As New List(Of Byte)
GetPrevValues(CurrentNode, Values)
'build our child nodes based on the direction we want.
Select Case direction
Case WindowsApplication7.Directions.Higher
For i As Byte = value + 1 To 10
If Not Values.Contains(i) Then
Dim node As New TreeNode(i.ToString)
CurrentNode.Nodes.Add(node)
'Calculate the children for each node
CalculateTreeNodes(node, directions)
End If
Next
Case WindowsApplication7.Directions.Lower
For i As Byte = 1 To value - 1
If Not Values.Contains(i) Then
Dim node As New TreeNode(i.ToString)
CurrentNode.Nodes.Add(node)
CalculateTreeNodes(node, directions)
End If
Next
End Select
End Sub
'recursive routine to find the parent values.
Private Sub GetPrevValues(CurrentNode As TreeNode, Values As List(Of Byte))
If Not CurrentNode Is Nothing Then
Values.Add(Byte.Parse(CurrentNode.Text))
GetPrevValues(CurrentNode.Parent, Values)
End If
End Sub
End Class
Public Enum Directions
Higher = 1
Lower = 0
End Enum
To find the longest branches you could use a conditional to check if directions is down to one character, then any children will be in the longest branches.