Building the BST (smaller goes left, larger goes right):
- 50 → root.
- 30 < 50 → left of 50. 70 > 50 → right of 50.
- 20 < 50, < 30 → left of 30. 40 < 50, > 30 → right of 30.
- 60 > 50, < 70 → left of 70. 80 > 50, > 70 → right of 70.
- 35 < 50, > 30, < 40 → left of 40.
The resulting tree is in the attached figure (height 3, with 35 the only node on the last level).
Traversals
- Inorder (Left, Root, Right): 20, 30, 35, 40, 50, 60, 70, 80 — sorted, as always for a BST.
- Preorder (Root, Left, Right): 50, 30, 20, 40, 35, 70, 60, 80
- Postorder (Left, Right, Root): 20, 35, 40, 30, 60, 80, 70, 50
— rhs