Imports System
Imports System.Collections.Generic
Public Class Program
Public Shared Sub Main(ByVal args As String())
Dim str1 As String = "abcdefg"
Dim str2 As String = "xayzgoe"
Dim count As Integer = CommonCharactersCount(str1, str2)
Console.WriteLine(count)
End Sub
Public Shared Function CommonCharactersCount(ByVal str1 As String, ByVal str2 As String) As Integer
Dim set1 As HashSet(Of Char) = New HashSet(Of Char)(str1)
Dim set2 As HashSet(Of Char) = New HashSet(Of Char)(str2)
set1.IntersectWith(set2)
Return set1.Count
End Function
End Class
' run:
'
' 3
'