Question 1

If the postorder traversal of an expression tree is 8, 2, +, 5, /, what is the numeric result of that Reverse Polish Notation expression?

Accepted Answer

A) 8 
B) 2 
C) 7 
D) 15 
A) 8 
B) 2 
C) 7 
D) 15

Question 2

Which of the following is NOT an example of a binary tree?

Accepted Answer

A) A decision tree where each interior node contains a question and the two subtrees correspond to a yes or no answer. 
B) An expression tree that shows the order of evaluation in an arithmetic expression. 
C) The family tree of a person, which includes all descendants of a person. 
D) A Huffman tree where the left and right turns on the paths to the leaves describe binary encodings. 
A) A decision tree where each interior node contains a question and the two subtrees correspond to a yes or no answer. 
B) An expression tree that shows the order of evaluation in an arithmetic expression. 
C) The family tree of a person, which includes all descendants of a person. 
D) A Huffman tree where the left and right turns on the paths to the leaves describe binary encodings.

Question 3

Insert the missing code in the following code fragment.This fragment is intended to create an iterator and access the first element in a tree.

Accepted Answer

A) Iterator iter = aTree.iterator(); B) Iterator iter = aTree.iterator(); C) Iterator iter = String.iterator(); D) Iterator iter = aTree.iterator(); A) Iterator iter = aTree.iterator(); B) Iterator iter = aTree.iterator(); C) Iterator iter = String.iterator(); D) Iterator iter = aTree.iterator();

Question 4

Consider the following tree diagrams:   Which of the above are binary trees?

Accepted Answer

A) Neither I nor II 
B) II only 
C) I only 
D) Both I and II 
A) Neither I nor II 
B) II only 
C) I only 
D) Both I and II

Question 5

Consider the following binary search tree diagram:   Consider the following pseudocode for the removal of a node n in a binary search tree:
 
If node D is to be removed, which action should be taken?

Accepted Answer

A) Swap the values in C and D so that C has A as its left child, then remove the new D node. 
B) Modify K to point to A as its left child, and modify A to point to F as its right child. 
C) Modify K to make its left child null. 
D) Modify K to point to F as its left child and modify F to point to A as its left child. 
A) Swap the values in C and D so that C has A as its left child, then remove the new D node. 
B) Modify K to point to A as its left child, and modify A to point to F as its right child. 
C) Modify K to make its left child null. 
D) Modify K to point to F as its left child and modify F to point to A as its left child.

Question 6

Consider the following tree diagram:   Which of the following nodes are root nodes?

Accepted Answer

A) R 
B) P 
C) C 
D) R and P 
A) R 
B) P 
C) C 
D) R and P

Question 7

A min-heap is a binary tree structure in which missing nodes may only occur where?

Accepted Answer

A) bottom level, left side 
B) left child of the root 
C) bottom level, right side 
D) anywhere in the bottom two levels 
A) bottom level, left side 
B) left child of the root 
C) bottom level, right side 
D) anywhere in the bottom two levels

Question 8

Consider the following binary search tree diagram:   Consider the following addNode method for inserting a newNode into a binary search tree:
public void addNode(Node newNode)
{
int comp = newnode.data.compareTo(data);
if (comp < 0)
{
if (left == null) {left = newNode;}
else { left.addNode(newNode); }
}
else
{
if (right == null) {right = newNode;}
else { right.addNode(newNode); }
}
}
Which nodes will be visited in order to insert the letter B into this tree, calling addNode on the root of the tree?

Accepted Answer

A) H, D, and A 
B) H and D only 
C) H only 
D) H, D, and F 
A) H, D, and A 
B) H and D only 
C) H only 
D) H, D, and F

Question 9

You are using a tree to show the evaluation order of arithmetic expressions.Which of the following statements is NOT correct?

Accepted Answer

A) Every level of the tree must contain an operator. 
B) Leaves contain numbers. 
C) The root contains an operator. 
D) Interior nodes contain operators. 
A) Every level of the tree must contain an operator. 
B) Leaves contain numbers. 
C) The root contains an operator. 
D) Interior nodes contain operators.

Question 10

Consider the following binary search tree diagram:   Consider the following pseudocode for the removal of a node n in a binary search tree:

If node J is to be removed, to which node will H point to instead of J?

Accepted Answer

A) X 
B) N 
C) M 
D) L 
A) X 
B) N 
C) M 
D) L

Question 11

A completely filled binary tree with a height of 3 has ____ nodes.

Accepted Answer

A) 12 
B) 6 
C) 7 
D) 8 
A) 12 
B) 6 
C) 7 
D) 8

Question 12

Consider a balanced binary tree with 520 nodes.The average length of all paths from the root to the leaves is approximately ____.

Accepted Answer

A) 10 
B) 12 
C) 9 
D) 13 
A) 10 
B) 12 
C) 9 
D) 13

Question 13

Which of the following statements about trees is NOT correct?

Accepted Answer

A) The root of the tree does not have a parent. 
B) A tree is composed of nodes. 
C) A node can have multiple parents. 
D) A node can have multiple child nodes. 
A) The root of the tree does not have a parent. 
B) A tree is composed of nodes. 
C) A node can have multiple parents. 
D) A node can have multiple child nodes.

Question 14

Which of the following statements about the three tree traversal schemes studied is correct?

Accepted Answer

A) Inorder traversal is used for copying file directories. 
B) Postorder traversal is used for copying file directories. 
C) Postorder traversal is used for removing file directories by removing subdirectories first. 
D) Inorder traversal is used for evaluating arithmetic expression trees on a stack-based calculator. 
A) Inorder traversal is used for copying file directories. 
B) Postorder traversal is used for copying file directories. 
C) Postorder traversal is used for removing file directories by removing subdirectories first. 
D) Inorder traversal is used for evaluating arithmetic expression trees on a stack-based calculator.

Question 15

Which of the following statements about a heap is correct?

Accepted Answer

A) A heap is a form of a binary search tree. 
B) When you traverse a heap in preorder, the nodes are in sorted order. 
C) The shape of a heap is irregular. 
D) The regular layout of a heap makes it possible to store heap nodes efficiently in an array. 
A) A heap is a form of a binary search tree. 
B) When you traverse a heap in preorder, the nodes are in sorted order. 
C) The shape of a heap is irregular. 
D) The regular layout of a heap makes it possible to store heap nodes efficiently in an array.

Question 16

If a min-heap has 1024 nodes, what is its height?

Accepted Answer

A) 10 
B) 12 
C) impossible to determine 
D) 11 
A) 10 
B) 12 
C) impossible to determine 
D) 11

Question 17

Which of the following statements about breadth-first and depth-first traversal is NOT correct?

Accepted Answer

A) Depth-first search goes deeply into the tree and then backtracks when it reaches the leaves. 
B) Breadth-first and depth-first search only work on a binary tree. 
C) Breadth-first search first visits all nodes on the same level before visiting the children. 
D) Depth-first search uses a stack to track the nodes that it visits. 
A) Depth-first search goes deeply into the tree and then backtracks when it reaches the leaves. 
B) Breadth-first and depth-first search only work on a binary tree. 
C) Breadth-first search first visits all nodes on the same level before visiting the children. 
D) Depth-first search uses a stack to track the nodes that it visits.

Question 18

In a binary search tree, where the root node data value = 45, what do we know about the data values of all the descendants in the left subtree of the root?

Accepted Answer

A) all will be  45 
C) approximately half the values are  45 
D) the root's left child value  45 
A) all will be  45 
C) approximately half the values are  45 
D) the root's left child value  45

Question 19

If the postorder traversal of an expression tree is 8, 2, +, 5, /, what is the preorder traversal?

Accepted Answer

A) /, +, 2, 8, 5 
B) 8, +, 2, /, 5 
C) /, +, 8, 2, 5 
D) +, /, 8, 2, 5 
A) /, +, 2, 8, 5 
B) 8, +, 2, /, 5 
C) /, +, 8, 2, 5 
D) +, /, 8, 2, 5

Question 20

Consider the following tree diagram:   What is the height of this tree?

Accepted Answer

A) 7 
B) 3 
C) 6 
D) 4 
A) 7 
B) 3 
C) 6 
D) 4

Exam 17: Tree Structures

If the postorder traversal of an expression tree is 8, 2, +, 5, /, what is the numeric result of that Reverse Polish Notation expression?

Which of the following is NOT an example of a binary tree?

Insert the missing code in the following code fragment.This fragment is intended to create an iterator and access the first element in a tree.

Consider the following tree diagrams: Which of the above are binary trees?

Consider the following binary search tree diagram: Consider the following pseudocode for the removal of a node n in a binary search tree: If node D is to be removed, which action should be taken?

Consider the following tree diagram: Which of the following nodes are root nodes?

A min-heap is a binary tree structure in which missing nodes may only occur where?

You are using a tree to show the evaluation order of arithmetic expressions.Which of the following statements is NOT correct?

Consider the following binary search tree diagram: Consider the following pseudocode for the removal of a node n in a binary search tree: If node J is to be removed, to which node will H point to instead of J?

A completely filled binary tree with a height of 3 has ____ nodes.

Consider a balanced binary tree with 520 nodes.The average length of all paths from the root to the leaves is approximately ____.

Which of the following statements about trees is NOT correct?

Which of the following statements about the three tree traversal schemes studied is correct?

Which of the following statements about a heap is correct?

If a min-heap has 1024 nodes, what is its height?

Which of the following statements about breadth-first and depth-first traversal is NOT correct?

In a binary search tree, where the root node data value = 45, what do we know about the data values of all the descendants in the left subtree of the root?

If the postorder traversal of an expression tree is 8, 2, +, 5, /, what is the preorder traversal?

Consider the following tree diagram: What is the height of this tree?

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