Lecture 18 - Trees

Question 1

When does the worst case happen for trees?

Answer 1

When it’s maximally unbalanced

Question 2

When do AVL trees balance themselves?

Answer 2

After inserts and deletes

Question 3

What are the properties of Binary Search trees? (3)

Answer 3

• The left subtree of a node contains only nodes with keys lesser than the node’s key.
• The right subtree of a node contains only nodes with keys greater than the node’s key.
• The left and right subtree each must also be a binary search tree.

Question 4

What do AVL trees do?

Answer 4

Keep the height of the left subtree and the height of the right subtree within a certain threshold (usually 1)