Imports System
Module TernarySearchDemo
Function TernarySearch(l As Integer, r As Integer, key As Integer, arr As Integer()) As Integer
While l <= r
Dim mid1 As Integer = l + (r - l) \ 3
Dim mid2 As Integer = r - (r - l) \ 3
If arr(mid1) = key Then
Return mid1
End If
If arr(mid2) = key Then
Return mid2
End If
If key < arr(mid1) Then
r = mid1 - 1
ElseIf key > arr(mid2) Then
l = mid2 + 1
Else
l = mid1 + 1
r = mid2 - 1
End If
End While
Return -1 ' not found
End Function
Sub Main()
Dim arr As Integer() = {1, 2, 8, 14, 15, 64, 78, 89, 99, 100, 110, 123}
Dim toSearch As Integer = 89
Dim index As Integer = TernarySearch(0, arr.Length - 1, toSearch, arr)
If index <> -1 Then
Console.WriteLine("Element found at index: " & index)
Else
Console.WriteLine("Element not found.")
End If
Console.ReadLine()
End Sub
End Module
' run:
'
' Element found at index: 7
'
