wex12/1

main v
	isRedBlack = false
if root == black
	isRedBlack = true
	node = root
	preorder(node)
if isRedBlack
	maxheight = height(root)
	minheight = use BFS to find smallest height 8)
	if (minheight * 2 + 1 > maxheight)
		isRedBlack = false

not main v
preorder(node)
  if (node == null)
    return
  checkTwoReds(node)
  if isRedBlack
	preorder(node.left)
  if isRedBlack
	preorder(node.right)

checkTwoReds(node)
	if node.color == red && (node.right == red || node.left == red)
		isRedBlack == false

height(node)
 if node == null
        return 0

    int lefth = height(node.left);
    int righth = height(node.right);

    return max(lefth,righth)