Imports System
Imports System.Collections.Generic
'===============================================================
' Node class: represents a general tree node stored as a
' binary tree using Left‑Child / Right‑Sibling representation.
'
' Left → first child
' Right → next sibling
'===============================================================
Public Class Node
Public Property Id As Integer
Public Property Name As String
Public Property Left As Node ' first child
Public Property Right As Node ' next sibling
Public Sub New(i As Integer, n As String)
Id = i
Name = n
Left = Nothing
Right = Nothing
End Sub
End Class
'===============================================================
' Print the tree with indentation
'===============================================================
Module TreePrinter
Public Sub PrintTree(root As Node, Optional depth As Integer = 0)
If root Is Nothing Then Exit Sub
' show ROOT explicitly on its own line
If depth = 0 Then
Console.WriteLine("ROOT")
End If
' indentation for the node itself
For i As Integer = 1 To depth + 1
Console.Write(" ")
Next
' print ID with leading zero if needed
Console.WriteLine($"{root.Id:00} - {root.Name}")
' first child
PrintTree(root.Left, depth + 1)
' next sibling
If depth = 0 AndAlso root.Right IsNot Nothing Then
' restart ROOT for next top-level node
PrintTree(root.Right, 0)
Else
PrintTree(root.Right, depth)
End If
End Sub
End Module
'===============================================================
' Build the tree using Left‑Child / Right‑Sibling representation
'===============================================================
Module TreeBuilder
Public Function BuildTree(
table As List(Of Tuple(Of Integer, String, Integer)),
nodesOut As Dictionary(Of Integer, Node)
) As Node
' Create nodes
For Each row In table
Dim id = row.Item1
Dim name = row.Item2
nodesOut(id) = New Node(id, name)
Next
Dim root As Node = Nothing
' Attach children and siblings
For Each row In table
Dim id = row.Item1
Dim parentId = row.Item3
Dim current = nodesOut(id)
If parentId = 0 Then
' top-level node → sibling chain under root
If root Is Nothing Then
root = current
Else
Dim p = root
While p.Right IsNot Nothing
p = p.Right
End While
p.Right = current
End If
Else
Dim parent = nodesOut(parentId)
' attach as first child or next sibling
If parent.Left Is Nothing Then
parent.Left = current
Else
Dim p = parent.Left
While p.Right IsNot Nothing
p = p.Right
End While
p.Right = current
End If
End If
Next
Return root
End Function
End Module
'===============================================================
' Main Program
'===============================================================
Module Program
Sub Main()
' Example table
' // Id Name ParentId
Dim table As New List(Of Tuple(Of Integer, String, Integer)) From {
Tuple.Create(1, "Node 1", 0),
Tuple.Create(2, "Node 1.1", 1),
Tuple.Create(3, "Node 2", 0),
Tuple.Create(4, "Node 1.1.1", 2),
Tuple.Create(5, "Node 2.1", 3),
Tuple.Create(6, "Node 2.3.1", 3),
Tuple.Create(7, "Node 1.2", 1),
Tuple.Create(8, "Node 1.3", 1),
Tuple.Create(9, "Node 1.3.1", 8),
Tuple.Create(10, "Node 2.4", 3),
Tuple.Create(11, "Node 2.1.1", 5),
Tuple.Create(12, "Node 2.1.1.6", 11)
}
Dim nodes As New Dictionary(Of Integer, Node)
' Build tree
Dim root As Node = TreeBuilder.BuildTree(table, nodes)
' Print tree
TreePrinter.PrintTree(root)
End Sub
End Module
'
' run:
'
' ROOT
' 01 - Node 1
' 02 - Node 1.1
' 04 - Node 1.1.1
' 07 - Node 1.2
' 08 - Node 1.3
' 09 - Node 1.3.1
' ROOT
' 03 - Node 2
' 05 - Node 2.1
' 11 - Node 2.1.1
' 12 - Node 2.1.1.6
' 06 - Node 2.3.1
' 10 - Node 2.4
'
