Imports System
Imports System.Collections.Generic
Public Class Program
Public Shared Sub Main(ByVal args As String())
Dim arr As Integer() = {2, 3, 4, 2, 1, 1, 7, 5, 8, 9, 5, 3}
' 4 + 7 + 8 + 9 = 28
Console.WriteLine(SumUniqueNumbers(arr))
End Sub
Public Shared Function SumUniqueNumbers(ByVal arr As Integer()) As Integer
Dim result As Integer = 0
Dim countAppearances As New Dictionary(Of Integer, Integer)
For Each num As Integer In arr
If countAppearances.ContainsKey(num) Then
countAppearances(num) += 1
Else
countAppearances(num) = 1
End If
Next
For Each kvp As KeyValuePair(Of Integer, Integer) In countAppearances
If kvp.Value = 1 Then
result += kvp.Key
End If
Next
Return result
End Function
End Class
' run:
'
' 28
'
