Imports System
Public Class Program
Public Shared Function countPairsWithSpecificDifference(ByVal arr As Integer(), ByVal difference As Integer) As Integer
Dim count As Integer = 0
Dim size As Integer = arr.Length
For i As Integer = 0 To size - 1
For j As Integer = i + 1 To size - 1
If arr(i) - arr(j) = difference OrElse arr(j) - arr(i) = difference Then
count += 1
End If
Next
Next
Return count
End Function
Public Shared Sub Main()
Dim arr As Integer() = {25, 16, 8, 12, 20, 17, 0, 4, 21, 26}
Dim difference As Integer = 4
' 7 pairs with difference 4: {25, 21}, {16, 12}, {16, 20}, {8, 12}, {8, 4}, {17, 21} {0, 4}
Console.WriteLine(countPairsWithSpecificDifference(arr, difference))
End Sub
End Class
' run:
'
' 7
'
