Afficher un X suivant des conditions croissantes ou décroissantes

Sub es()
 Dim i As Long
 For i = 2 To Cells(Rows.Count, 1).End(3).Row
  If Cells(i, 1) = Cells(i - 1, 1) Or Cells(i, 1) > Cells(i - 1, 1) Then z = 1
  If Cells(i, 1) < Cells(i - 1, 1) And z = 1 Then Cells(i, 2) = "X": z = 0
  If Cells(i, 1) = Cells(i - 1, 1) Or Cells(i, 1) < Cells(i - 1, 1) And Cells(i, 1) > Cells(i + 1, 1) Then w = 1
  If Cells(i, 1) > Cells(i - 1, 1) And w = 1 Then Cells(i, 2) = "X": w = 0
  Next i
End Sub

=INDIRECT("A"&MAX(SI(Feuil1!$B$1:$B1<>"";LIGNE(Feuil1!$B$1:$B1));1)&":A"&LIGNE())

=REPT("X";NON((INDEX(P;1)=MIN(P))*(INDEX(P;LIGNES(P))=MAX(P))+(INDEX(P;1)=MAX(P))*(INDEX(P;LIGNES(P))=MIN(P))))

=SI(ET($C1<>"X";SIGNE($A1-DECALER($A$1;MAX(($B$1:$B1="X")*LIGNE($B$1:$B1));0))=-SIGNE($A2-$A1));"X";"")

Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
If Target.Address <> "$B$1" Then Exit Sub
Dim t, rest(), deb&, fin&, i&, x, j&, y, sens%
Cancel = True
t = Range("A1", Range("A" & Rows.Count).End(xlUp)(2)) 'au moins 2 éléments
ReDim rest(1 To UBound(t), 1 To 1)
deb = 2
fin = UBound(t) - 1
1 For i = deb To fin
  '---détermination du sens---
  If i = deb Then
    x = t(i - 1, 1)
    For j = i To fin
      y = t(j, 1)
      sens = IIf(y > x, 1, IIf(y < x, -1, 0))
      If sens Then Exit For
    Next
    i = j
  End If
  '---détermination de l'interruption de série---
  If sens = 1 And t(i, 1) < t(i - 1, 1) Or sens = -1 And t(i, 1) > t(i - 1, 1) Then
    rest(i, 1) = "X"
    deb = i + 1
    GoTo 1
  End If
Next
'---restitution---
[B1].Resize(UBound(rest)) = rest
End Sub

=REPT("X";ET($B1<>"X";$A2<>$A1;SIGNE($A1-DECALER($A$1;MAX(($B$1:$B1="X")*LIGNE($B$1:$B1));0))=-SIGNE($A2-$A1)))