Function RevIntersect(arr1() As String, arr2() As String) As String()
Dim sResult, aux As New List(Of String)()
aux.AddRange(arr1)
aux.AddRange(arr2)
For Each elem As String In aux
If (Not arr1.Contains(elem) OrElse Not Arr2.Contains(elem)) AndAlso _
Not sResult.Contains(elem) Then
sResult.Add(elem)
End If
Next
Return sResult.ToArray()
End Function
https://code.google.com/p/google-diff-match-patch/