Imports System
Imports System.Collections.Generic
Public Class FindElementThatAppearsOnceInArray_VB
Public Shared Function FindElementThatAppearsOnceInArray(ByVal arr As Integer()) As Integer
Dim map As Dictionary(Of Integer, Integer) = New Dictionary(Of Integer, Integer)()
For Each x As Integer In arr
If map.ContainsKey(x) Then
map(x) += 1
Else
map(x) = 1
End If
Next
For Each entry As KeyValuePair(Of Integer, Integer) In map
If entry.Value = 1 Then
Return entry.Key
End If
Next
Return -1
End Function
Public Shared Sub Main(ByVal args As String())
Dim arr As Integer() = New Integer() {3, 5, 5, 2, 7, 3, 2, 8, 8, 3, 2, 5, 8}
Console.WriteLine(FindElementThatAppearsOnceInArray(arr))
End Sub
End Class
' run:
'
' 7
'
