Getting hash of a list of strings regardless of order

Question

I would like to write a function GetHashCodeOfList() which returns a hash-code of a list of strings regardless of order. Given 2 lists with the same strings sho

Answer 1

    Dim list1 As ArrayList = New ArrayList()
    list1.Add("0")
    list1.Add("String1")
    list1.Add("String2")
    list1.Add("String3")
    list1.Add("abcdefghijklmnopqrstuvwxyz")

    Dim list2 As ArrayList = New ArrayList()
    list2.Add("0")
    list2.Add("String3")
    list2.Add("abcdefghijklmnopqrstuvwxyz")
    list2.Add("String2")
    list2.Add("String1")
    If GetHashCodeOfList(list1) = GetHashCodeOfList(list2) Then
        Stop
    Else
        Stop
    End If
    For x As Integer = list1.Count - 1 To 0 Step -1
        list1.RemoveAt(list1.Count - 1)
        list2.RemoveAt(list2.Count - 1)
        Debug.WriteLine(GetHashCodeOfList(list1).ToString)
        Debug.WriteLine(GetHashCodeOfList(list2).ToString)
        If list1.Count = 2 Then Stop
    Next


Private Function GetHashCodeOfList(ByVal aList As ArrayList) As UInt32
    Const mask As UInt16 = 32767, hashPrime As Integer = Integer.MaxValue
    Dim retval As UInt32
    Dim ch() As Char = New Char() {}
    For idx As Integer = 0 To aList.Count - 1
        ch = DirectCast(aList(idx), String).ToCharArray
        For idCH As Integer = 0 To ch.Length - 1
            retval = (retval And mask) + (Convert.ToUInt16(ch(idCH)) And mask)
        Next
    Next
    If retval > 0 Then retval = Convert.ToUInt32(hashPrime \ retval) 'Else ????
    Return retval
End Function