Tìm kiếm nhị phân bằng VBA

binary_search.bas

Function BinarySearch(strArray() As String, strSearch) As Long
    Dim Left As Long, Middle As Long, Right As Long
    Left = 1
    Right = UBound(strArray, 1)
    
    Do While Left <= Right
        Middle = Left + (Right - Left) / 2
        
        If strSearch = strArray(Middle, 1) Then
            BinarySearch = Middle
            Exit Function
        End If
        
        If strSearch > strArray(Middle, 1) Then
            Left = Middle + 1
        Else
            Right = Middle - 1
        End If
    Loop
    
    BinarySearch = -1
End Function