Sub mac()
       Dim arr1(1 To 101) As String
       Dim arr2(1 To 101) As String
       Dim i As Integer, j As Integer
       i = 1
       j = 1
          
       For i = 1 To 100
           arr1(i) = Cells(1, i)
       Next i
       arr1(101) = "end"
          
       For i = 1 To 100
           If arr1(i) = "A" And arr1(i + 1) = "B" Then
               arr2(j) = "AB"
               j = j + 1
             '  i = i + 1
           ElseIf arr1(i) = "B" And arr1(i + 1) = "A" Then
               arr2(j) = "BA"
               j = j + 1
             ' i = i + 1
           ElseIf arr1(i) = "B" And arr1(i + 1) = "C" Then
               arr2(j) = "BC"
               j = j + 1
              ' i = i + 1
           End If
       Next i
       arr2(101) = "end"
          
       'джаст проверка, что есть в массиве arr2
       i = 1
       While i < j
           MsgBox arr2(i)
           i = i + 1
       Wend
       '#################################
          
       i = 1
       While i < j
           If arr2(i) = "AB" And arr2(i + 1) = "BA" Then
               MsgBox "совпадение пары АБ и БА"
           ElseIf arr2(i) = "AB" And arr2(i + 1) = "BC" Then
               MsgBox "совпадение АБ и БС"
           End If
           i = i + 1
       Wend
End Sub