Sub maybe()
'https://www.mrexcel.com/forum/excel-questions/1066730-parent-child-hierarchy.html
'CODING ASSUMES input data is on worksheet called "input data" & results go to worksheet "output"
Dim i As Long
Dim lColumn As Long
Dim sThisChild As String
Dim sThisParent As String
Dim rng As Excel.Range
Dim ar As Variant
ar = Worksheets("input data").Range("A1").CurrentRegion.Value2
With Worksheets("output")
.Cells.Clear
'start with first data and populate worksheet..
'Put first data in worksheet, from row 2 of input data
.Cells(1, 1).Value2 = ar(2, 1)
.Cells(2, 1).Value2 = "+"
.Cells(2, 2).Value2 = ar(2, 2)
'Now loop through all others
For i = LBound(ar, 1) + 2 To UBound(ar, 1)
sThisParent = ar(i, 1)
sThisChild = ar(i, 2)
'check if the parent is already in the worksheet
Set rng = .Cells.Find(What:=sThisParent, LookAt:=xlWhole)
If rng Is Nothing Then
'Parent data is not yet on the worksheet.
'This new data can be posted to the worksheet's first row or become the new last row.
'Make it the last row for consistency with image posted in question.
'Work out the current last row,
Set rng = .Cells.Find(What:="*", After:=.Range("A1"), SearchOrder:=xlByRows, SearchDirection:=xlPrevious)
.Cells(rng.Row + 1, 1) = sThisParent
.Cells(rng.Row + 2, 1).Value2 = "+"
.Cells(rng.Row + 2, 2) = sThisChild
Else
'Parent data is already on the worksheet. So add this data as a child to it.
'if there is not yet a child,
If Len(rng.Offset(1, 1).Value2) = 0 Then
rng.Offset(1).EntireRow.Insert
rng.Offset(1).Value2 = "+"
rng.Offset(1, 1).Value2 = sThisChild
Else
'find end of this branch
lColumn = rng.Column
Do
Set rng = rng.Offset(1, 1)
Loop Until Len(rng.Offset(1, 1).Value2) = 0
rng.Offset(1).EntireRow.Insert
.Cells(rng.Row + 1, lColumn).Value2 = "+"
.Cells(rng.Row + 1, lColumn + 1).Value2 = sThisChild
End If
End If
Next i
End With
End Sub
