-- parent script "BinaryTreeTraversal"

on inOrder (me, node, l)
  if voidP(l) then l = []
  if voidP(node) then return l
  if not voidP(node.getLeft()) then l = me.inOrder(node.getLeft(), l)
  l.add(node)
  if not voidP(node.getRight()) then l = me.inOrder(node.getRight(), l)
  return l
end

on preOrder (me, node, l)
  if voidP(l) then l = []
  if voidP(node) then return l
  l.add(node)
  if not voidP(node.getLeft()) then l = me.preOrder(node.getLeft(), l)
  if not voidP(node.getRight()) then l = me.preOrder(node.getRight(), l)
  return l
end

on postOrder (me, node, l)
  if voidP(l) then l = []
  if voidP(node) then return l
  if not voidP(node.getLeft()) then l = me.postOrder(node.getLeft(), l)
  if not voidP(node.getRight()) then l = me.postOrder(node.getRight(), l)
  l.add(node)
  return l
end

on levelOrder (me, node)
  l = []
  queue = [node]
  repeat while queue.count
    node = queue[1]
    queue.deleteAt(1)
    l.add(node)
    if not voidP(node.getLeft()) then queue.add(node.getLeft())
    if not voidP(node.getRight()) then queue.add(node.getRight())
  end repeat
  return l
end

-- print utility function
on serialize (me, l)
  str = ""
  repeat with node in l
    put node.getValue()&" " after str
  end repeat
  delete the last char of str
  return str
end