Module modPerm
 
    Const GEN_NEXT As Integer = 0  'ok, print and continue
    Const GEN_TERM As Integer = 1  'ok, terminate
 
    Private Function gen_perm_rep_init(ByVal vector() As UInteger) As Integer
        For i As Integer = 0 To vector.Length - 1
            vector(i) = CUInt(i)
        Next i
        Return GEN_NEXT
    End Function
 
    Private Function gen_perm_rep_next(ByVal vector() As UInteger, _
        ByVal n As UInteger) As Integer
 
        Dim j As Integer = CInt(n) - 2  'index
        Dim i As Integer = CInt(n) - 1 'help index
        Dim temp As UInteger     'auxiliary element
 
        Do While j >= 0 AndAlso vector(j + 1) <= vector(j)
            j -= 1
        Loop
        If j < 0 Then Return GEN_TERM
 
        Do While (vector(i) <= vector(j))
            i -= 1
        Loop
        temp = vector(j)
        vector(j) = vector(i)
        vector(i) = temp
        i = CInt(n)
 
        Do While j < i
            j += 1 : i -= 1
            If j < i Then
                temp = vector(j)
                vector(j) = vector(i)
                vector(i) = temp
            End If
        Loop
        Return (GEN_NEXT)
    End Function
 
    Public Function Permutationen_Ohne_Wiederholung(Of T) _
        (ByVal elements() As T) As List(Of T())
 
        Dim vector(elements.Length - 1) As UInteger
        Dim n As UInteger = CUInt(vector.Length)
 
        Dim lst As New List(Of T())
        Dim gen_result As Integer = gen_perm_rep_init(vector)
        Do While gen_result = GEN_NEXT
            Dim ielements(elements.Length - 1) As T
            For i As Integer = 0 To vector.Length - 1
                ielements(i) = elements(CInt(vector(i)))
            Next
            lst.Add(ielements)
            gen_result = gen_perm_rep_next(vector, n)
        Loop
        Return lst
    End Function
End Module