Binary Trees

• A

• B

• C

Answer explanation

B has a node with three children, so it is not a Binary Tree.

• A

• C

• E

• I

Answer explanation

A is the only node with no parent node, so it is the root.

How many child nodes can each node have in a Binary Tree? Select all that apply.

• 0

• 1

• 2

• 3

Answer explanation

Nodes of a Binary Tree can have up to two child nodes.

Consider a binary tree where A is the parent of B and C, B is a parent of D and E, E is a parent of F. G and H are children of C, and I and J are children of H.

On what level is J?

• Root

• Level 1

• Level 2

• Level 3

Answer explanation

J is a child of H, which is a child of C, which is a child of A (the root). Because there were three jumps between J and the root, J is said to be on level 3.

• A

• B

• C

Answer explanation

An infix traversal reveals the correct expression.

• A

• B

• C

• D

Answer explanation

An infix traversal reveals the correct expression.

• 0

• 20

• 25

• 86

Answer explanation

An infix traversal reveals the correct expression to evaluate.

• A

• C

• E

• F

Answer explanation

E has no child nodes, so it is a leaf.

Which of these is the preorder traversal of the given tree?

• 1 4 9 5 8 2 3

• 1 5 3 2 4 8 9

• 1 4 9 8 5 2 3

• 1 4 5 9 8 2 3

Answer explanation

For each node, check the left child recursively, then the right child recursively.

Which of these is the post order traversal of the given tree?

• 2 3 5 9 8 4 1

• 4 8 9 5 3 2 1

• 8 9 3 2 4 5 1

• 8 9 4 3 2 5 1

Answer explanation

Recursively, check the left child node, then the right child node, and finally the parent node.