T{
	left;
	right;
	parent;
	key;
}root, node;

TREE-INSERT-ROOT(T)
Podaj root.key
root.left=NIL
root.right=NIL
root.parent=NIL

TREE-INSERT (T, node, root)
Podaj node.key
y = NIL
x = T.root
while x != NIL do
y = x
if node.key < x.key then x = x.left
else x = x.right
node.p = y
if y == NIL then T.root = node
else if node.key < y.key then y.left = node
else y.right = node

PREORDER-TREE-WALK (node)
if node != NIL then
if node.left=NIL or node.right=NIL then node.key=1
else if node.left=NIL and node.right=NIL then node.key=2
else node.key=0
wypisz (node.key)
PREORDER-TREE-WALK (node.left)
PREORDER-TREE-WALK (node.right)