Data Abstraction & Problem Solving with C++ Walls and Mirrors, 7th edition Frank M Carrano Test Bank

Data Abstraction & Problem Solving with C++ Walls and Mirrors, 7th e BY Frank M. Carrano

Email: richard@qwconsultancy.com

Chapter 1 Questions Multiple Choice Questions The specifications of an ADT’s operations indicate ______. a. what the operations do b. how to implement the operations c. how to store the data in the ADT d. how to carry out the operations Answer: a.

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Data structures are part of an ADT’s ______. a. definition b. implementation c. specifications d. usage Answer: b.

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A(n) ______ allows two modules to communicate with each other. a. data structure b. axiom c. interface d. client Answer: c.

An ADT’s ______ govern(s) what its operations are and what they do. a. specifications b. implementation c. documentation d. data structure Answer: a.

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5.

When each module performs one well-defined task, we say that it is ___. a. loosely coupled b. highly coupled c. cohesive d. not easily reused Answer: c.

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When should an operation contract be written? a. during analysis b. after coding c. at the same time as user documentation d. when taking initial notes from client Answer: a.

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What information is included in the operation contract? a. the method’s interface b. data flow among the modules c. assumptions about input d. all of these Answer: d.

8.

What kind of interface contains a method if and only that method is essential to that class’s responsibilities? a. complete b. minimal

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Chapter 1 Questions c. d.

Answer: b.

expanded compact

9.

What must be known about the ADT Bag in order to use it in a program? a. how entries in the bag are represented b. how bag operations are implemented c. how many entries can be stored in the bag d. the interface of the bag Answer: d.

10. According the CRC specifications for a Bag, which of the following behaviors would not be one of the responsibilities of the class Bag? a. See if the bag is empty b. See if the bag is full c. Look at all the objects in the bag d. Count the number of times a certain object occurs in the bag Answer: b.

11. A client program depends solely on the ______ of the ADT. a. data members b. structure c. implementation d. behavior Answer: d.

12. What should a programmer do before implementing a recently designed class? a. write code that uses the class b. check comments that document specifications c. adjust the design when problems are discovered d. all of these Answer: d 13. Object-oriented programming views a program as ______. a. a sequence of actions b. a collection of classes c. a group of methods d. an interaction among objects Answer: d.

14. An ADT’s operations are known as its ______. a. axioms b. methods c. variables d. interfaces Answer: b.

15. Encapsulation combines an ADT’s data with its operations to form a(n) ______. a. exception b. method c. object d. variable Answer: c.

16. A(n) ______ is a C++ construct that enables a programmer to define a new data type.

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Chapter 1 Questions a. b. c. d.

Answer: a.

class method data field object

17. A C++ class contains data members and ______. a. clients b. interfaces c. methods d. data structures Answer: c.

18. A(n) ______ is an instance of a class. a. method b. data field c. interface d. object Answer: d.

19. A(n) ______ is a class that inherits the members of another class. a. base class b. superclass c. abstract class d. subclass Answer: d.

20. A function can indicate that an error has occurred by ______ an exception. a. throwing b. catching c. implementing d. declaring Answer: a.

21. To ______ an exception means to deal with the error condition. a. declare b. catch c. implement d. try Answer: b.

22. Which of the following are ways to address unusual situations? a. simply assume the invalid situation will never occur b. guess at the client’s intention c. return a value that signals a problem d. all of the above are options Answer: d.

23. For the method remove(anEntry) of the ADT Bag, what would be the output of the method? a. anEntry b. nothing c. true or false d. the previous position of anEntry in the bag Answer: c

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Chapter 1 Questions 24. What is the task of the toVector() method of the ADT Bag? a. copy the entries of the bag into a vector b. vector the entries to the printer c. test to see if there is a vector to the bag d. remove all objects from the bag Answer: a 25. Understanding what the problem is and what the requirements of a solution are is called a. Object Oriented Analysis b. Object Oriented Design c. Object Oriented Solution d. Algorithmic Oriented Design Answer: a.

26. Objects collaborate when they a. are cohesive b. are used by a programming team c. send each other messages d. model a real life situation Answer: c.

27. Which of the following could not be a module? a. a standalone function b. a data member c. a class method d. a class itself Answer: b.

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Chapter 1 Questions True/False Questions 1.

According to the principle of information hiding, a module should be completely isolated from other modules.

Answer: False.

2. Data structures are part of an ADT’s implementation.

Answer: True.

3. An abstract data type is another name for a data structure.

Answer: False.

4.

An interface for a class that allows programmers to accomplish any reasonable task is called a complete interface.

Answer: True 5. It is possible to use one ADT to implement another ADT. Answer: True 6. An application can use the operations of an ADT without knowing how the ADT is implemented.

Answer: True.

7. By default, all members in a class are public.

Answer: False.

8. A highly cohesive module is less robust.

Answer: False 9. Highly coupled modules should be avoided.

Answer: True 10. Any instance of a subclass can be used in a program anywhere that an instance of the superclass can be used.

Answer: True.

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Chapter 1 Questions Short Answer Questions 1.

What are some of the benefits of modularity?

Answer: A modular problem is easier to write, read, and modify. Modularity also isolates errors and eliminates redundancies.

2.

What is functional abstraction?

Answer: Functional abstraction is a design principle that separates the purpose and use of a module from its implementation.

3.

What is information hiding?

Answer: Information hiding is a process that hides certain implementation details within a module and makes them inaccessible from outside the module.

4.

What are the three types of operations on a data collection?

Answer: The three types of operations on data are: a. Add data to a data collection. b. Remove data from a data collection. c. Ask questions about the data in a data collection.

5.

What is data abstraction?

Answer: Data abstraction is a design principle that separates the operations performed on a collection of data from the implementation of the operations.

6.

What is an abstract data type (ADT)?

Answer: An ADT is a collection of data together with a set of operations on that data.

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What is a data structure?

Answer: A data structure is a construct that is defined within a programming language to store a collection of data.

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What does an operation contract do?

Answer: An operation contract documents how a method can be used and what limitations it has. It specifies the module’s purpose, assumptions, input, and output.

9.

What are some ways you can address unusual situations?

Answers: a. Assume an invalid situation will not occur b. Ignore invalid situations c. Guess at client’s intentions d. Return a value that signals a problem e. Throw an exception

10. What is a bag?

Answer: A bag is a container of a finite number of objects having the same data type and in no particular order. It can contain duplicate items.

11. Define the client of a class?

Answer: The client of a class is a program or module that uses the class.

12. What is the purpose of an exception?

Answer: Exceptions are used for indicating errors during the execution of a program.

13. What does inheritance allow the system designer to do?

Answer: Inheritance allows the programmer to reuse classes previously defined for a related purpose. It

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Chapter 1 Questions extends the implementation or makes slight modifications 14. What are the three principles of object oriented programming?

Answers: Encapsulation, inheritance, and polymorphism 15. What are the advantages of a highly cohesive module?

Answer: A highly cohesive module will be well named, promoting self-documenting and easily understood code. It can be easy to reuse in other projects. It is easier to maintain. It will be more robust, less likely to be affected by change.

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Chapter 2 Questions Multiple Choice Questions 1.

In a recursive solution, the ______ terminates the recursive processing. a) local environment b) pivot item c) base case d) recurrence relation Answer: c.

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A binary search uses a ______ strategy. a) divide-and-conquer b) sequential c) determine-the-pivot d) smallest-to-largest Answer: a.

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A ______ is a mathematical formula that generates the terms in a sequence from previous terms. a) local environment b) pivot item c) base case d) recurrence relation Answer: d.

4.

The factorial of n is equal to ______. a) n – 1 b) n – factorial (n–1) c) factorial (n–1) d) n * factorial (n–1) Answer: d.

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The base case for a recursive definition of the factorial of n is ______. a) factorial (–1) b) factorial (0) c) factorial (n) d) factorial (n – 1) Answer: b.

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What is fundamentally wrong with computing the Fibonacci sequence recursively? a) it has two base cases b) each call to the function results in two recursive calls c) it computes the same values over and over d) nothing Answer: c.

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In the box trace, each box roughly corresponds to a(n) ______. a) recursive relation b) activation record c) base case d) pivot item Answer: b.

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In the box trace, each box contains all of the following EXCEPT ______. a) the values the function’s arguments b) the function’s local variables c) the function’s execution time

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Chapter 2 Questions d) a placeholder for the value returned by each recursive call from the current box e) the value returned by the function itself Answer: c.

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In the box trace for a recursive function, a new box is created each time ______. a) the function is called b) the function returns a value c) an object is created d) an object is initialized Answer: a.

10. What happens if a recursive function never reaches a base case? a) the function returns the correct value b) the function returns an incorrect value c) the function terminates immediately d) an infinite sequence of recursive calls occurs Answer: d.

11. In a recursive method that writes a string of characters in reverse order, the base case is ______. a) a string with a length of 0 b) a string whose length is a negative number c) a string with a length of 3 d) a string that is a palindrome Answer: a.

12. Which of the following is a precondition for a method that accepts a number n and computes the nth Fibonacci number? a) n is a negative integer b) n is a positive integer c) n is greater than 1 d) n is an even integer Answer: b.

13. How many bases cases does a recursive binary search of a sorted array have? a) 0 b) 1 c) 2 d) 3 Answer: c.

14. The number of ways to choose k out of n things is ______. a) the number of ways to choose k – 1 out of n – 1 things b) the number of ways to choose k out of n – 1 things c) the sum of the number of ways to choose k – 1 out of n – 1 things and the number of ways to choose k out of n – 1 things d) the product of the number of ways to choose k – 1 out of n – 1 things and the number of ways to choose k out of n – 1 things Answer: c.

15. When you solve a problem by solving two or more smaller problems, each of the smaller problems must be ______ the base case than the original problem. a) closer to b) farther to c) either closer to or the same “distance” from d) either farther to or the same “distance” from Answer: a.

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Chapter 2 Questions 16. A recursive method that computes the number of groups of k out of n things has the precondition that ______. a) n is a positive number and k is a nonnegative number b) n is a nonnegative number and k is a positive number c) n and k are nonnegative numbers d) n and k are positive numbers Answer: c.

17. The midpoint of a sorted array has the index ______, where first is the index of the first item in the array, and last is the index of the last item in the array. a) first / 2 + last / 2 b) first / 2 – last / 2 c) (first + last) / 2 d) (first – last) / 2 Answer: c.

18. If the value sought by a recursive binary search algorithm is in the array, which of the following is true? a) the algorithm makes the same comparisons as a sequential search b) the algorithm is successful without reaching a base case c) the algorithm searches the entire array d) the algorithm searches only the array half containing the value Answer: d.

19. Which of the following is NOT a precondition for an array that is to be searched by a recursive binary search algorithm? (first is the index of the first item in the array, last is the index of the last item in the array, and SIZE is size of the array) a) SIZE <= first b) 0 <= first c) last <= SIZE – 1 d) anArray[first] <= anArray[first + 1] <= … <= anArray[last] Answer: a.

20. What does the following recursive algorithm display? writeBack(in s:string) if (s is empty) return else { Write the first character of s writeBack(the string beginning at the second character of s) } a) nothing b) the first character of s a number of times equal to the length of s c) the string s d) the string s backward Answer: c.

21. For an array containing 2, 3, 5, 6, 9, 13, 16, and 19, what value does a recursive binary search algorithm return when it searches for 6? a) 1 b) 3 c) 4 d) none of the above Answer: b.

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Chapter 2 Questions 22. For an array containing 2, 3, 5, 6, 9, 13, 16, and 19, what value does a recursive binary search algorithm return when it searches for 10? a) –1 b) 0 c) 1 d) 10 Answer: a.

23. In a sorted array having SIZE locations, the kth smallest item is given by ______. a) anArray[k-1] b) anArray[k] c) anArray[SIZE-k] d) anArray[SIZE+k] Answer: a.

24. A recursive binary search algorithm always reduces the problem size by ______ at each recursive call. a) 1 b) 2 c) half d) one-third Answer: c.

25. A recursive solution that finds the factorial of n always reduces the problem size by ______ at each recursive call. a) 1 b) 2 c) half d) one-third Answer: a.

26. In the recursive solution to finding the kth smallest item in an array, the problem size decreases by ______ at each recursive call. a) 1 b) at least 1 c) half d) at least half Answer: b.

27. In the recursive solution to the Towers of Hanoi problem, the number of disks to move ______ at each recursive call. a) decreases by 1 b) increases by 1 c) decreases by half d) increases by half Answer: a.

28. A recursive solution that finds the factorial of n generates ______ recursive calls. a) n - 1 b) n c) n + 1 d) n * 2 Answer: b.

29. In the Fibonacci sequence, which of the following integers comes after the sequence 1, 1, 2, 3? a) 3 b) 4

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Chapter 2 Questions c) 5 d) 6 Answer: c.

30. Which of the following is a base case for a recursive binary search algorithm? (first is the index of the first item in the array, last is the index of the last item in the array, and mid is the midpoint of the array). a) last > first b) first > last c) 0 <= first d) last <= SIZE-1 Answer: b.

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Chapter 2 Questions True/False Questions 1. A recursive solution solves a problem by solving a smaller instance of the same problem.

Answer: True.

2. An iterative solution involves loops.

Answer: True.

3. A binary search starts at the beginning of the collection of items.

Answer: False.

4. An iterative method always calls itself.

Answer: False.

5. In practice, recursion should be used even when a problem has a simple iterative solution.

Answer: False.

When constructing a recursive solution, you should assume that a recursive call’s postcondition is true if its precondition is true.

Answer: True.

6.

7. Every recursive method must have a base case.

Answer: True.

8. A recursive solution can have more than one base case.

Answer: True.

9. The binary search algorithm can be applied to an unsorted array.

Answer: False.

10. The base case for a recursive solution to finding the kth smallest item in an array cannot be predicted in advance.

Answer: True.

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Chapter 2 Questions Short Answer Questions 1. What items does a sequential search examine when it is successful?

Answer: A sequential search starts at the beginning of the collection and looks at every item in the collection in order until the desired item is found.

2. What is a base case?

Answer: A base case is a special case of a recursive function whose solution you know. A base case enables the recursive processing to terminate.

3. What are the four questions that must be considered when constructing a recursive solution?

Answer: The four questions that must be considered when constructing a recursive solution are: • How can you define the problem in terms of a smaller problem of the same type?

• How does each recursive call diminish the size of the problem?

• What instance of the problem can serve as the base case?

• As the problem size diminishes, will you reach this base case?

4. What is a recurrence relation?

Answer: A recurrence relation is a mathematical formula that generates the terms in a sequence from previous terms.

5. What is the box trace?

Answer: The box trace is a systematic way to trace the actions of a recursive method.

6. What is an activation record?

Answer: An activation record is a record that contains a method’s local environment at the time of and as a result of the call to the method.

7. What elements are included in a method’s local environment?

Answer: The local environment of a method includes the method’s local variables, a copy of the actual value arguments, a return address in the calling routine, and the value of the method itself.

8. What are the two base cases for a recursive binary search algorithm?

Answer: The two base cases are: • first > last • value == anArray[mid] where first is the index of the first item in the array anArray, last is the index of the last item in anArray, and mid is the midpoint of anArray.

When is the base case first > last (where first is the index of the first item in the array and last is the index of the last item in the array) reached in a recursive binary search algorithm?

Answer: This base case is reached when the value sought is not in the original array.

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10. When is the base case value == anArray[mid] (where mid is the midpoint of the array) reached in a recursive binary search algorithm?

Answer: This base case is reached when the value sought is in the original array.

11. What is a pivot item?

Answer: A pivot item is an element of a data collection that an algorithm uses to arrange the rest of the collection.

12. What is the base case for the recursive solution to the Towers of Hanoi problem?

Answer: The base case for the recursive solution to the Towers of Hanoi problem is a tower containing only one disk.

13. What are the two factors that contribute to the inefficiency of some recursive solutions?

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Chapter 2 Questions Answer: The two factors are the overhead associated with method calls, and the inherent inefficiency of some recursive algorithms.

14. What is a tail-recursive function?

Answer: A tail-recursive function is a function whose last action is a recursive call.

15. Why do some compilers automatically replace tail recursion with iteration?

Answer: Some compilers automatically replace tail recursion with iteration because tail-recursive methods are often less efficient than their iterative counterparts, and the conversion of a tail-recursive method to an equivalent iterative method is rather mechanical.

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Chapter 3 Questions Multiple Choice 1. Which of the following provides a way to enforce the wall of an ADT? a. Implement the ADT as a C++ class b. Always use public fields c. Never use private records together methods d. Link records together Answer: A 2. Each method for the array based implementation of the ADT bag will require access to the array of entries and what else? a. The number of fields b. The current number of entries in the bag c. The ID of the previous bag entry d. The ID of the next bag entry Answer B 3. The default constructor for an array implementation of the ADT Bag should do what? a. Load the bag with blanks and zeros b. Set itemCount to DEFAULT_CAPACITY c. Initialize the current number of items d. Load the new entry with blanks and zeros Answer: C 4. Why should we prevent a client’s direct access to a data structure? a. To protect the job security of the systems analyst b. It is a federal law c. Most computer languages do not allow it d. The client could possibly damage the ADT’s data Answer: D 5. Which of the following methods would definitely be considered part of a core group? a. add b. findNext c. clear d. search Answer: A 6. An add method that encounters a full array should either signal it’s client or a. Crash the program b. Allocate a larger array c. Loop back to the beginning of the array for another pass through the array d. Merely increment the loop counter into the next area of memory Amswer: B 7. Rather than returning a value, a method can signal its client by a. Crashing the program b. Beeping c. Throwing an exception d. Ignoring the requested record Answer: C .

Chapter 3 Questions 8. What did the method getCurrentSize return? a. The value of DEFAULT_CAPACITY b. The value stored in maxItems c. The ID of the most recently added element d. The value stored in itemCount Answer: D 9. What is the type of the value returned by the method isEmpty? a. bool b. int c. real d. long Answer: A 10. Which method uses a while loop to cycle through an array’s indices from 0 to itemCount – 1, comparing a given object to every object in the array? a. delete b. getFrequencyOf c. toVector d. isFull Answer: B 11. What method could be easily defined by calling getFrequencyOf? a. itemCount b. isEmpty c. add d. delete Answer: C 12. What was the method recommended to avoid gaps in the array when an element is removed? a. Shift all the entries beyond the new gap back one slot b. Shift all the entries in front of the new gap up one slot c. Set the pointer in the entry before the gap to the entry after the gap d. Replace the entry being removed with the last entry in the array Answer: D 13. What is an easy way for the method clear to make the bag appear empty? a. Set itemCount to zero b. Set all the data values in all the entries to blanks and zeros c. Set itemCount to maxItems – 1 d. Set maxItems to zero Answer: A

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Chapter 3 Questions True or False 1. Specifications indicate how to implement ADT operations, but not what the operations do Answer: False 2. Generally it is unwise to define an entire class then attempt to test it Answer: True 3. The method getIndexOf should generally be declared as private.

Answer: True 4. Data structures for an ADT can be determined at any time during the process of specifying its operations.

Answer: False 5. C++ arrays are data structures Answer: True 6. Choices made during the implementation process have no effect on execution time of your code.

Answer: False 7. According to the text, when adding a first entry to an array, always place it in the first element, the element whose index is zero.

Answer: False 7. The method toVector must “know” where the add has placed the entries.

Answer: True 8. The client of a class can access the class’s private members directly by use of a password.

Amswer: False 9. The entries in a bag have no particular order.

Answer: True

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Chapter 3 Questions Short Answer 1. Why would we set the default capacity of ArrayBag to a low number when we are first implementing it?

Answer: So we can test our design to handle a full bag situation 2. How can we keep a method from being able to alter a class’s data members?

Answer: Make it a const method 3. Why do public data members make more difficult the debugging a program’s logic.

Answer: You would need to look for errors outside of the class. This greatly increases the number of lines of code you must review.

4. What did the method toVector do in the initial core group presented in the text?

Answer: Get the entries that are in a bag and return them to the client within a vector. It uses a simple loop to add the bag’s entries to the vector.

5. When a stub is used within a test program, what should it do?

Answer: report that was invoked by displaying a message.

6. What is the purpose of using longer mnemonic names for loop variables?

Answer: to make their intent clearer to the person reading a program 7. What are the three problems mentioned concerning an array full of gaps?

Answer: a) itemCount – 1 is no longer index of last item in the array, b) method contains will have to waste time looking at empty array elements, c) when items[maxItems – 1] is occupied, the bag could occur full, even when it is not 8. Why would the reference bag.itemCount be illegal within the client?

Answer: this is within the private portion of the class 9. You decide to use recursion in your implementation. Consider method getIndexOf. You use a variable searchIndex to work your way through the array. What would be the two base cases?

Answer: items[searchIndex] is the entry you seek or searchIndex equals itemCount

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Chapter 4 Questions Multiple Choice 1. What is used to start accessing a linked chain of nodes? a. The head pointer b. item[0] c. item[1] d. The null pointer Answer: A 2. What value should headPtr contain if there are no nodes for it to point to? a. The boolean value TRUE b. nullptr c. The constant ZERO d. The constant NULL Answer: B 3. Given the following poorly written code sequence: headPtr = new Node<std::string>(); headPtr = nullptr; What is the result? a. headPtr points to the new node b. Access the new node by use of headPtr c. The new node is inaccessible d. The program crashes Answer: C 4. In a link-based implementation, what node is the only one to which we have direct access? a. The last b. All are equally direct access c. The one at nullPtr d. The first Answer: D 5. Which of the following methods needs a counter? a. getFrequencyOf b. toVector c. add d. remove Answer: A 6. What type does the method contains return? a. int b. bool c. string d. ItemType Answer: B 7. What must be done with a node that is removed from the bag? .

Chapter 4 Questions a. Set it to nullptr b. Decrement itemCount c. Use the delete command so system can use returned memory d. return canRmoveItem Answer: C 8. A destructor’s name is a(n) ? followed by the class name. a. ^ b. $ c. @ d. ~ Answer: D 9. When copying an object involves only copying the values of its data members, the copy is called a(n) ? . a. shallow copy b. deep copy c. transfer copy d. virtual copy Answer: A 10. What object oriented feature can we use to have a single test program, with one set of method calls in which the user can decide which bag implementation (array- or link-based) needs testing? a. copy constructor b. polymorphism c. toVector d. the case statement Answer: B 11. Which of the following are a good reason for using an array-based implementation of a bag? a. An array is not fixed size b. You must traverse n entries to get to the nth item in the array c. Requires less memory than a link-based implementation d. Good choice for a large bag Answer: C 12. Which of the following are a good reason for using a link-based implementation of a bag? a. A link list is fixed size. b. You can access nodes directly with equal access time c. A link-based implementation is good choice for a small bag d. Linked chains do not have a fixed size Answer: D 13. Given the following method from the class Node: What does this method do? a. setItem b. getItem c. setNext d. setPrevious

template<class ItemType> void Node<ItemType>::doSomething(const ItemType& anItem) { item = anItem; }

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Chapter 4 Questions Answer: A 14. Given the following method from the class LinkedBag What does this method do? template<class ItemType> bool LinkedBag<ItemType>::doSomething(const ItemType& anEntry) const { return (getPointerTo(anEntry) != nullptr); }

a. setItem b. contains c. isEmpty d. destructor Answer: B

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Chapter 4 Questions True or False 1. A node can be dynamically allocated.

Answer: True 2. Before you can assign headPtr a value, you must first create a new Node object.

Answer: False 3. Generally speaking, a link-based implementation does not impose a fixed maximum size on the data structure.

Answer: True 4. Like an array-based implementation, a link-based implementation’s insertion and removal operations will need to move data items.

Answer: False 5. For a link-based bag, the most convenient place to make an insertion is at the beginning of the chain.

Answer: True 6. Even though you have allocated memory by using new, there is no need to deallocate it with the delete command.

Answer: False 7. The method clear cannot simply set ItemCount to zero.

Answer: True 8. A class can have multiple destructors.

Answer: False 9. According to the text, you must write a destructor if your class allocates memory dynamically.

Answer: True 10. Classes that use dynamically allocated memory can depend on the compiler-generated destructor.

Answer: False 11. The copy constructor for our bag class requires traversing the original linked chain and duplicating each node visited.

Answer: True 12. A recursive version of toVector is complicated and requires invocation of the copy constructor.

Answer: False 13. Access time is a constant for an array-based implementation.

Answer: True 14. A link-based implementation requires less memory than an array-based implementation.

Answer: False

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Chapter 4 Questions 15. The following method is recursive. template<class ItemType> void LinkedBag<ItemType>::fillVector(std::vector<ItemType>& bagContents, Node<ItemType>* curPtr) const { if (curPtr != nullptr) { bagContents.push_back(curPtr– >getItem()); fillVector(bagContents, curPtr– >getNext()); } // end if } // end fillVector

Answer: True

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Chapter 4 Questions Short Answer 1. What are the contents of a node?

Answer: data and a link or reference to another node 2. Name two of the private members of the class LinkedBag Answer: any two of -- headPtr, itemCount, method getPointerTo 3. What steps must be done to implement the toVector method in a link-based implementation of the ADT Bag? Answer: use headPtr to get to first node, use links to traverse through the nodes, as you visit each node, copy its data item into the vector 4. What private method does the method remove invoke?

Answer: getPointerTo 5. When is a destructor implicitly invoked?

Answer: At the end of the block in which the object was created.

6. Give three situations that will invoke the copy constructor.

Answer: any three of the following a. Use assignment operator to assign an object to a variable b. Pass an object to a function by value c. Return an object from a valued function d. Define and initialize an object 7. What are two possible problems with using an array-based bag implementation Answer: any two of the following a. Arrays have a fixed size b. Hard to predict maximum number of items in the bag c. If the array is made too large, computer memory is wasted d. Increasing the size of a dynamically allocated array can waste storage and time 8. Given the following method, what does it do? template<class ItemType> int LinkedBag<ItemType>::doSomething(const ItemType& anEntry) const { int x = 0; int counter = 0; Node<ItemType>* curPtr = headPtr; while ((curPtr != nullptr) && (counter < itemCount)) { if (anEntry == curPtr– >getItem()) { x++; } counter ++; curPtr = curPtr– >getNext(); } return x; }

Answer: get the frequency of a specified entry in a bag.

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Chapter 5 Questions Multiple Choice 1. What program sees whether a given string is a member of the language? a. The compiler b. A word processor c. An encryption program d. A text editor Answer: A 2. What states the rules of a language? a. The compiler b. The grammar c. The English teachers d. The computer teachers Answer: B 3. From the symbols of grammar given by the text, what is used to signify “x or y”? a. x ^ y b. x % y c. x | y d. x && y Answer: C 4. Given the expression a + b. a. prefix b. postfix c. outfix d. infix Answer: D

What type of expression is this?

5. Term “infix” indicates that every binary operator appears where? a. between its operands b. after its operands c. before its operands d. before each operand Answer: A 6. In what type of expression does an operator precede its operands? a. postfix b. prefix c. outfix d. infix Answer: B 7. Given infix expression a + b Which of the following is the equivalent postfix expression? a. b + a b. + a b c. a b + d. + a b + Answer: C

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Chapter 5 Questions 8. Given the infix expression a + (b * c) Which of the following is the equivalent prefix expression? a. a b c * + b. c * b + a c. a b c * + d. + a * b c Answer: D 9. What do we call the strategy used for guessing at a solution and backing up when an impasse is reached? a. backtracking b. impasse resolution c. modified guessing d. back guessing Answer: A 10. Which of the following has the more involved grammar? a. postfix b. infix c. prefix d. reflex Answer: B

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Chapter 5 Questions True or False 1. All programs are strings, but not all strings are programs.

Answer: True 2. The language Algebraic Expressions is the set of strings that meets certain rules of syntax and that definition also gives the rules of the syntax.

Answer: False 3. A given word, s, is a palindrome if and only if, the first and last characters of s are the same and s minus its first and last characters is a palindrome.

Answer: True 4. The stricter a definition, the harder it is to recognize a syntactically legal expression.

Answer: False 5. The following expression is a prefix expression + a b – c d Answer: True 6. Subproblems that a recursive search solution generates need not reach a base case.

Answer: False 7. You can use induction to prove that a recursive algorithm either is correct or performs a certain amount of work.

Answer: True 8. Little relationship exists between mathematical induction and recursion.

Answer: False

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Chapter 5 Questions Short Answer 1. According to the text of what elements make up a language such as English or C++ ?

Answer: a set of strings of symbols from a finite alphabet 2. It is possible to write a straightforward recursive algorithm that determines whether a given string is in the language. Such an algorithm is called a(n) ____________________________ for the language.

Answer: recognition algorithm

11. Given this syntax diagram: It is a diagram for what in the C++ language?

Answer: identifiers

3. Give two examples of words that are palindromes Answer: possible words … radar, deed, wow, mom, redder, pullup, kayak, madam, refer, rotor, solos, kook, noon, peep, poop, toot, aha, bob, bub, dad, boob, bib, eve, ewe, eye, gag, gig, …

4. To use infix expressions, what other rules does this convention necessitate?

Answer: associativity rules, precedence rules, use of parentheses.

5. Given the infix expression (( a + b) * c Convert it to a prefix expression.

Answer: * + a b c 6. What two things must be true for an expression to be in prefix form?

Answer: The first character of the string is an operator, the remainder of the string consists of two consecutive prefix expressions.

7. Evaluate this postfix instruction 3 5 + 2 * Answer: 16 8. Evaluate this postfix expression 67 42 - 5 / Answer: 5 9. Evaluate this postfix expression 3 16 6 - * 5 / Answer: 6 10. Evaluate this prefix expression + 6 * - 3 2 4 Answer: 2 11. Evaluate this prefix expression: * 4 – 5 6 Answer: 4 12. What possible wrong choices might an algorithm make when searching for a sequence of flights between cities?

Answer: hits a dead end; algorithm might cycle through same sequence of cities

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Chapter 5 Questions 13. How many moves are required to solve the Towers of Hanoi problem with 5 disks?

Answer: 31 14. What are the three steps for a proof by induction?

Answer: a. Show the property is true for N = 1 b. Assume the property is true for N = k c. Show that the property is true for N = k + 1

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Chapter 6 Questions Multiple Choice Questions 1.

What is the corrected input if the line yww<dshr<<wd<e is typed on a keyboard, where < represents the backspace character? a. ywdswe b. ywwdwde c. ywdshwe d. ywdswd Answer: a.

2.

If the array 6, 2, 7, 13, 5, 4 is added to a stack, in the order given, which number will be the first number to be removed from the stack? a. 6 b. 2 c. 5 d. 4 Answer: d.

3.

The item that is removed first from a stack is called the ______ of the stack. a. front b. top c. base d. prime Answer: b.

4.

If the array 6, 21, 35, 3, 6, 2, 13 is added to a stack, in the order given, which of the following is the top of the stack? a. 2 b. 6 c. 3 d. 13 e. 35 Answer: d.

5.

What behavior does the ADT stack exhibit? a. first in, first out b. first in, never out c. last-in, first-out d. last in, last out Answer: c.

6.

The ______ operation of the ADT stack adds an item to the top of the stack. a. isEmpty b. push c. pop d. peek Answer: b.

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Chapter 6 Questions 7.

The ______ operation of the ADT stack retrieves and then removes the top of the stack. a. isEmpty b. push c. pop d. peek Answer: c.

8.

The ______ operation of the ADT stack retrieves the top of the stack, but does not change the stack. a. isEmpty b. push c. pop d. peek Answer: d.

9.

Which of the following operations of the ADT stack accepts a parameter? a. push b. isEmpty c. peek d. destroyStack Answer: a.

10. Which of the following strings contains balanced braces? a. ab{cde{fg}hi{jkl} b. ab{cde{fghi}j}kl} c. {abc{de}{fg}hij}kl d. {ab{cde{fgh}ijkl} Answer: c.

11. If a stack is used by an algorithm to check for balanced braces, which of the following is true of a balanced braces string once the end of the string is reached? a. the stack is empty b. the stack has one “{” c. the stack has one “}” d. the stack has one “{” and one “}” Answer: a.

12. Given the language L, where: L = {w$w’ : w is a possibly empty string of characters other than $, w’ = reverse(w) } which of the following strings is NOT in L? a. XY$YX b. Z$Z c. $ d. XYZ$ZXY Answer: d.

13. Which of the following is NOT true about converting infix expressions to postfix expressions? a. the operands always stay in the same order with respect to one another b. the operators always stay in the same order with respect to one another c. an operator will move only “to the right” with respect to the operands d. all parentheses are removed Answer: b.

14. Which of the following is the postfix form of the infix expression: (a + b) * c / d a. a b + c * d /

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Chapter 6 Questions b. a b * c / d + c. a + b * c / d d. a b + c d * / Answer: a.

15. What is the value of the following postfix expression: 5 2 – 8 4 + *? a. -9 b. 28 c. 35 d. 36 Answer: d.

16. In a graph that represents the flight map for the HPAir problem, if a flight exists from city C 1 to city C2, C2 is said to be ______ C1. a. adjacent to b. similar to c. related to d. bordering Answer: a.

17. In a graph that represents the flight map for the HPAir problem, if a flight exists from city C 1 to city C2, the path from C1 to C2 is called a _______. a. relation b. neighborhood c. directed path d. connecting path Answer: c.

18. ______ are considered when choosing the next city to visit in a stack-based nonrecursive solution to the HPAir problem. a. All cities b. All unvisited cities adjacent to the destination city c. All cities adjacent to the city on the top of the stack d. All unvisited cities adjacent to the city on the top of the stack Answer: d.

19. An algorithm that uses a stack to implement a nonrecursive solution to the HPAir problem reaches the conclusion that there is no path from an origin city to a destination city only after ______. a. the algorithm has backtracked to the origin b. the algorithm has backtracked to the origin and there remain no unvisited cities to fly to from the origin c. the algorithm has reached a city and there remain no unvisited cities to fly to from that city d. the algorithm has reached the destination and there remain no unvisited cities to fly to from the destination Answer: b.

20. Typically, ______ are used by a compiler to implement recursive methods. a. linked-lists b. arrays c. stacks d. queues Answer: c.

21. When a recursive call to a function occurs, the compiler’s implementation must remember all of the following information EXCEPT ______. a. values of parameters b. values of local variables

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Chapter 6 Questions c. values of global variables d. a reference to the point from which the recursive call was made Answer: c.

22. The ______ operation of the ADT stack retrieves and then removes the top of the stack.

a. isEmpty b. push c. pop d. peek

Answer: C 23. A stack is initially empty, then the following commands are performed:

push 5, push 7, pop, push 10, push 5, pop which of the following is the correct stack after those commands (assume the top of the stack is on the left)? a. 5 10 7 5 b. 5 10 c. 7 5 d. 10 5 Answer: D 26. Consider the peek() operation for the ADT Stack as described by the author. What is its output?

a. true or false a. there is no output b. the object that is at the top of the stack c. the number of items left on the stack Answer: C. 28. Which of the following is a good analogy of the ADT Stack?

a. people standing in a cafeteria line b. a paper bag with colored poker chips c. a group of people playing musical chairs d. a pile of textbooks on your desk Answer: D. 29. Consider the push(newEntry) operation of the ADT Stack. What is the output of the operation?

a. true or false b. there is no output c. the object that is at the top of the stack d. the number of items left on the stack Answer: A. 30. Why would axioms be specified for an ADT.

a. to determine the cost of development b. specify the behavior of the ADT c. to determine possible uses of the ADT d. to determine which ADT should be used Answer: B. 31. Which of the following is not a listed outcome of the exhaustive search strategy described in the text?

a. You go around in circles forever b. It is impossible to reach a city because no flights go there c. You eventually reach the destination city

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Chapter 6 Questions d. You reach a city C from which there are no departing flights Answer: B

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Chapter 6 Questions True/False Questions 1.

If 5 items are added to a stack, the first item to be removed from the stack is the first item that was added to the stack.

Answer: False.

2. A stack has a first in, first out property.

Answer: False.

3. The peek operation of the ADT stack changes the stack.

Answer: False.

4. A program can use the operations of the ADT stack without knowing how the operations are implemented.

Answer: True.

5.

If the characters in a string are added to a stack one at a time, characters removed from the stack will occur in the order in which they appear in the original string.

Answer: False.

6.

When infix expressions are converted to postfix expressions, the operands always stay in the same order with respect to one another.

Answer: True.

7. According to the author, the LIFO property of stacks seems inherently unfair.

Answer: True

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Chapter 6 Questions Short Answer Questions 1. What is meant by the last-in, first-out (LIFO) property?

Answer: The LIFO property is a property of a stack whereby the last item placed on the stack will be the first item removed from it.

2. What is the difference between the stack pop and peek operations?

Answer: The pop operation removes the top of the stack. The peek operation retrieves the top of the stack, but does not remove it.

3.

In a program that uses a stack to check for balanced braces in an string, what condition indicates that the braces are balanced when the end of the string is reached?

Answer: The braces in a string are balanced if the stack is empty when the end of the string is reached.

4. What restriction does the array-based implementation of a stack place on the push operation?

Answer: The array-based implementation of a stack prevents the push operation from adding an item to the stack when the array is full.

5. What are the three facts about converting from infix expressions to postfix expressions?

Answer: The three facts are: • The operands always stay in the same order with respect to one another.

• An operator will move only “to the right” with respect to the operands.

• All parentheses are removed.

6.

What factors determine the placement of operators when an infix expression is converted to a postfix expression?

Answer: The factors that determine the placement of operators are parentheses, operator precedence, and left-toright association.

7. What is a directed path?

Answer: A directed path is a sequence of directed edges that begins at one vertex and ends at another vertex in a directed graph.

8. What is an exhaustive search?

Answer: An exhaustive search is a search strategy that must examine every item in a collection of items before it can determine that the item sought does not exist.

9. If a stack is used in a nonrecursive solution to the HPAir problem, when is it necessary to backtrack from a city?

Answer: It is necessary to backtrack from a city whenever there are no more unvisited cities to fly to from that city.

10. What is an activation record?

Answer: An activation record is a record that contains a method’s local environment at the time of and as a result of the call to the method.

15. What operations were identified for the ADT Stack?

Answer: • See whether the stack is empty • Add a new item • Remove from the stack the item that was added most recently • Get the item that was added to the stack most recently (without removing) 16. Following are the steps in the process to convert from infix to postfix form. Put them in the correct order by writing the number of the step in the blank to the left.

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Chapter 6 Questions _____ When you encounter a “)”, pop operators off the stack and append them to the end of postfixExp until you encounter the matching “(“ _____ Push each “(“ onto the stack _____ When you reach the end of the string, pop the remaining contents off the stack and append them to the end of postfixExp. _____ When you encounter an operand, append it to postfixExp _____ When you encounter an operator, if the stack is empty, push the operator onto the stack. However, if the stack is not empty, pop operators of greator or equal precedence from the stack and append them to postfixExp, stopping when you encounter a “(“ or an operator of lower precedence or when the stack becomes empty. You then push the current operator in the expression onto the stack.

Answer: 4, 2, 5, 1, 3

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Chapter 7 Questions Multiple Choice Questions

1.

When is an array based implementation of the ADT stack not a better choice? a) the stack can be large, but often is not b) the stack does not exceed the fixed size of the array c) the stack is most always right around 80 characters d) the stack represents the number of students in a typical class Answer: a.

2.

When should a constructor use an initializer? a) when the value of the data member needs validation b) when the stack is full c) when the value of the data member has no restrictions d) when the stack is empty Answer: C. 3.

What is accomplished by hiding implementations of a stack in a class? a) client code can access any entries of the stack b) only the top of the stack can be accessed by client code c) you can also treat the ADT as a queue d) the code runs faster Answer: B 4.

In a link-based implementation of a stack you must write both a copy constructor and a) a virtual constructor b) a virtual destructor c) a sort() method d) a virtual instructor Answer: B. What command is used to enforce a precondition that the peek() method cannot work on an empty stack. a) result = false; b) if (top < MAX_STACK - 1) c) return top < 0; d) assert (!isEmpty()); Answer: D. 5.

6. Given the following code: template < class ItemType> ArrayStack<ItemType>::ArrayStack() : top(-1) { } What method is this? a) the default destructor b) the virtual destructor c) the default constructor d) the copy constructor Answer: C. 7. Given the following code: template < class ItemType> bool ArrayStack<ItemType>::doSomething() { bool result = false ; if (!isEmpty())

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Chapter 7 Questions { top--; result = true ; } return result; } What method is this? a) pop() b) peek() c) default constructor d) copy constructor Answer: A 8. Given the following code: template < class ItemType> ItemType ArrayStack<ItemType>::doSomething() const { assert (!isEmpty()); return items[top]; } What method is this? a) pop() b) peek() c) default constructor d) copy constructor Answer: B. 9.

If you implement a stack using an array, where should the bottom element of the stack be placed? a) at the end of the array b) mid array for a binomial search c) at the first element of the array d) it doesn’t matter Answer: C 10. If you implement a stack using a chain of linked nodes that has a head pointer, where should the top of the stack be placed for easiest and fastest access? a) at the first node of the chain b) at the top of the tree structure c) at the last node of the chain d) it doesn’t matter Answer: A. 11. Why would a stack be a poor choice for implementing an ADT bag? a) it might fill up b) you couldn’t account for duplicates c) you need to be able to look through all the elements in the bag, not just the top of the stack d) actually it would be a good choice Answer: C. 12. What kind of method might be most useful during program debugging? a) return the bottom element of the stack b) display the contents of the whole stack c) sort the items in the stack d) reverse the order of the items in the stack Answer: B.

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Chapter 7 Questions 13. Given the following code: template < class ItemType> LinkedStack<ItemType>::~doSomething() { while (!isEmpty()) pop(); } What does this method do? a) it is the destructor b) it is the constructor c) it displays the contents of the whole stack d) if the stack is not empty, it returns the top of the stack Answer: A. 14. The return type of the peek() operation in the array-based and pointer-based implementations of a stack is a) ItemType b) bool c) int d) assert Answer: A. 15. In the array based implementation of a stack class, what does the constructor initialize the private variable top to? a) 0 b) -1 c) 1 d) MAX_STACK Answer: B 16. In the linked based implementation of a stack class, what does the default constructor initialize the private variable topPtr to? a) OrigChainPtr b) newChainPtr c) nullPtr d) 0 Answer: C. 17. In the linked based implementation of a stack class, what method besides push() allocates a new node? a) pop() b) display() c) default constructor d) copy constructor Answer: D. 18. In designing a link based implementation of the stack, what standard exception did the author decide to ignore? a) bad_alloc b) logic_error c) PrecondViolatedExcep d) nullPtrError Answer: A. 19. In the array based implementation of the stack is an if statement if (top < MAX_STACK – 1) … // What is this checking for? a) a null pointer error b) does the stack have room for a new entry

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Chapter 7 Questions c) is the array empty d) where should we put the new entry Answer: B. 20. Given this graphic of an array based stack.

What would be returned by a call to the method peek() a) b) c) d) Answer: D

2 10 20 30

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Chapter 7 Questions True/False Questions

1. A program can use the operations of the ADT stack without knowing how the operations are implemented.

Answer: True.

2. In an array based implementation of a stack, the stack can grow and shrink dynamically.

Answer: False 3.

In the link based implementation of the stack, both the method push and the copy constructor allocate new nodes.

Answer: True 4. Private data members are hidden from the client.

Answer: True 5. A class need not validate data given by client code. According to the author, the client code should do that.

Answer: False 6. In both implementations of the class stack, the pop methods returned a value of type bool.

Answer: True

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Chapter 7 Questions Short Answer Questions 1. What is the difference between the stack pop and peek operations?

Answer: The pop operation removes the top of the stack. The peek operation retrieves the top of the stack, but does not remove it.

2. What restriction does the array-based implementation of a stack place on the push operation?

Answer: The array-based implementation of a stack prevents the push operation from adding an item to the stack when the array is full.

3. What is the purpose of using an assert or throwing an exception in the peek method?

Answer: It enforces the precondition that the stack must contain at least one entry for the peek to be used.

4. In the array implementation of a stack, why should items and top be specified as private?

Answer: You ensure that client code cannot violate the ADT’s walls. Otherwise the client could access entries in the array directly instead of using the ADT stack operations.

5. Why must both a copy constructor and a virtual destructor be used in implementing a stack with a linked list?

Answer: Memory is allocated dynamically. A shallow copy is insufficient, it would only copy the pointer topPtr. The copy constructor is needed to make a copy of all the nodes in the linked stack.

6. Give an example of when a link based implementation of a stack is a better choice.

Answer: A link based implementation would be required if a stack is occasionally large, but most of the time is not.

Otherwise, memory is wasted in a large array that is rarely required.

7.

When writing a constructor how do you decide whether to use an initializer versus the set method to give initial values to the values of a class’s data members> Answer: Use an initializer if the value of the data members has no restrictions. Use a set method if the value of the data member needs validation. Alternatively you could have the constructor perform its own validation.

8. Why did the author decide not to deal with a bad_alloc exception in designing the link based stack?

Answer: Even though both push and the copy constructor allocate new nodes and could fail if the system has no spare memory available, this would probably not happen in the simple applications we are working with. Also most computing systems today do not have severely restricted memory size.

9. In an array based implementation of a stack, why is the bottom of the stack the first element of the array?

Answer: There is no need to move or shift entries in the array when adding or removing entries of the stack.

10. In a link based implementation of a stack, why should the first node of the stack contain the top of the stack?

Answer: It provides easiest and fastest addition and removal operations.

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Chapter 8 Questions Multiple Choice Questions 1.

How is the order of the entries of an ADT list determined? a) by the list itself b) by the client c) by the operating system d) the order doesn’t matter Answer: B. Which element of the list does not have a unique predecessor? a) the head of the list b) the tail of the list c) the middle element of the list d) all have unique predecessors Answer: A. 2.

Changing the value of an entry at a given position on the list would probably be the task of which of these methods? a) replace b) get c) push d) insert Answer: A. 3.

e) f) g) h) i) Answer: C

What type would the getLength method for a list return? boolean ItemType integer void

Which of the following list methods would have only one parameter? a) isEmpty b) setEntry c) insert d) remove Answer: D 4.

Which of the following methods from list would have no parameters and void for the return type? a) setEntry b) getEntry c) insert d) clear Answer: D. 5.

Given bList: snibble, nibble, tribble, wibble, quibble. bList.insert(3, Bob) is executed. What is the appearance of the list? a) snibble, nibble, tribble, Bob, wibble, quibble b) snibble, nibble, Bob, tribble, wibble, quibble c) snibble, nibble, tribble, wibble, quibble, Bob, Bob, Bob d) Bob, Bob, Bob, snibble, nibble, tribble, wibble, quibble Answer: B. 6.

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The command

Chapter 8 Questions Given bList: bob, slob, snob, cob, hob, rob and the operation bList.remove(4) is executed. What does the list become? a) bob, slob, snob, hob, rob b) bob, slob, snob, cob, rob c) bob, slob d) hob, rob Answer: A. 7.

Given cList: bip, snip, pip, rip, dip, clip. What value would be returned by the call to method cList.getEntry(3)? a) bip b) snip c) pip d) rip Answer: C. 8.

9. Given cList: bip, snip, pip, rip, dip, clip. What value would be returned by the call to method cList.insert(9, sip)? a) true b) false c) it throws an exception d) sip Answer: B. 10. What should be returned by the list operation (aList.insert(2,x)).getEntry(2) ? a) false b) 2 c) x d) an exception is thrown Answer: C. 11. What would be returned by the list operation (bList.insert(3,x)).remove(3)? a) 2 b) x c) false d) bList Answer: D. 12. Consider nameList of size 12. For the operation nameList.insert(Clyde,x), which of the following would be an invalid value for x? a) 0 b) 1 c) 3 d) 12 Answer: A 13.

Given the commands below, what do they do? n = 0 for (position = 1 through intList.getLength()) n+= intList.getEntry(position) a) insert integers into the list b) sum the values found in list c) sum the numbers 0 through n d) calculate n!

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Chapter 8 Questions Answer: B. 14.

Given the commands below, what do they do? for (position = 1 through aList.getLength()/2) { a = aList.getEntry(aList.getLength()-position+1) aList.setEntry(aList.getEntry(aList.getLength()-position+1)) aList.setEntry(a,position) } a) randomize the entries b) sort the entries c) reverse the order of the entries d) count how many entries there are Answer: C.

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Chapter 8 Questions True/False Questions 1. The ADT list can have an arbitrary length.

Answer: True.

2. Insertion at the end of a linear linked list is a special case.

Answer: False.

3. Lists contain items of the same type.

Answer: True 4. Items in a list may be referenced by number.

Answer: True 5.

When you specify the behavior of list operations, always take into consideration how you might implement them.

Answer: False 6. An axiom that describes the behavior of our ADT list is that a newly created list is empty.

Answer: True 7. (newList()).isEmpty() Answer: True 8. The task of displaying all the items in a list is not an ADT list operation.

Answer: True 9. In the ADT list, each entry in the list is identified by its position which is an integer beginning with 0.

Answer: False 10. Inserting a new entry into a list renumbers any existing entries that follow the new one in the list.

Answer: True

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Chapter 8 Questions Short Answer Questions 1. What two characteristics are important for the entries in an ADT list?

Answer: The entries have position and they are ordered 2. Describe what happens when we insert a new item into the middle of the list.

Answer: All items that had position numbers greater or equal to the position to which we insert it must have their position numbers increased by 1 after the insertion. In effect they must be shifted one step higher in the list.

3. Give the definition of the ADT List Answer: A finite number of objects, not necessarily distinct, having the same data type and ordered by their positions as determined by the client.

4. What is needed besides a set of axioms in order to define the behavior of an ADT’s operations completely?

Answer: a set of preconditions and post conditions.

5. What would we expect this for loop to do? for (position = 1 through aList.getLength()) { dataItem = aList.getEntry(position) print(dataItem) } Answer: display all the items of the list 6. What is the range of entry numbers for which it is legal to insert a new entry?

Answer: from 1 through 1 greater than the current size of the list.

7. When an entry is removed from a list, what is an additional consequence of that removal?

Answer: any existing entries that follow the deleted one are renumbered.

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Chapter 9 Questions Multiple Choice Questions 1.

A pointer variable contains the ______ of a memory cell. a. content b. address c. data type d. ADT Answer: b.

2.

The members of a node structure can be accessed with the ______ operator. a. [] b. & c. -> d. at Answer: c.

3.

A pointer variable whose sole purpose is to locate the first node in a linked list is called ______. a. the list’s top b. the node’s link c. the list’s link d. the list’s head Answer: d.

4.

A(n) ______ operation sequentially visits each node in a linked list. a. access b. delete c. get d. traverse Answer: d.

5.

To remove a node N from a linear linked list, you will need to ______. a. set the pointer next in the node that precedes N to point to the node that follows N b. set the pointer next in the node that precedes N to point to N c. set the pointer next in the node that follows N to point to the node that precedes N d. set the pointer next in N to point to the node that follows N Answer: a.

Which of the following statements deletes the node to which cur points? a. prev->next = cur; b. cur->next = prev; c. cur->next = cur->next; d. prev->next = cur->next; Answer: d.

6.

7.

Which of the following statements deletes the first node of a linear linked list that has 10 nodes? a. head->next = cur->next; b. prev->next = cur->next; c. head = head->next; d. head = NULL; Answer: c.

8.

Which of the following statements inserts a new node, pointed to by newPtr, at the end of a linear linked list? a. newPtr->next = cur; prev->next = newPtr;

.

Chapter 9 Questions b. c. d.

newPtr->next = head; head = newPtr; newPtr->next = NULL; prev->next = cur; newPtr->next = cur;

Answer: a.

9.

A ______ allows the deletion of a node from a linked list without the need to traverse the list to establish a trailing reference. a. head pointer b. dummy head node c. tail pointer d. precede pointer Answer: d.

10. The author suggests that when you first look at implementing an ADT List, that “list” is simply a fancy name for a. an array b. a bag c. a linked list d. a stack Answer: a.

11. What operation does the ADT List have that an array does not? a. identify their items by number b. getLength() c. insertItem() d. isEmpty() Answer: B. 12. When designing an array based implementation of an ADT List, which of the following are not specified as private? a. items b. itemCount c. clear() d. maxItems Answer: C. 13. What is the return type of the list operator remove(int position)? a. void b. int c. itemType d. bool Answer: D. 14. Which of the following operators uses two parameters? a. insert b. getLength c. remove d. clear Answer: A. 15. Given the following diagram.

.

Chapter 9 Questions

What list operation does this depict? a. deleting an item in the list b. inserting an item in the list c. expanding the array to make it larger d. counting the number of items in the list Answer: B. 16. To thoroughly test the insert method in an array-based implementation of ADT List, what other method do we need? a. clear b. remove c. getEntry d. the constructor Answer: C. 17. Given the following diagram.

What list operation does this depict? a. deleting an item in the list b. inserting an item in the list c. expanding the array to make it larger d. counting the number of items in the list Answer: A. 18. In the author’s array based implementation of the ADT List, to what one variable does the clear method assign a value? a. items[0] b. items[maxItems] c. position d. itemCount Answer: D. 19. In the list based implementation of the ADT List, which of the following is not a private variable in the classe? a. headPtr b. isEmpty c. itemCount d. getNodeAt Answer: B 20. Given the following diagram.

.

Chapter 9 Questions

What List action does this depict? a. insert a new node b. get the value stored at a node c. remove a node from the chain d. get the value stored at a node Answer: C. 21. In the link based implementation of the ADT List, what method does the destructor call? a. remove b. insert c. isEmpty d. clear Answer: D. 22. Given the following pseudocode logic: if ( the insertion position is 1 ) Add the new node to the beginning of the chain else

Ignore the first node and add the new node to the rest of the chain What does this describe? a. recursive addition of a node to the list b. iterative addition of a node to the list c. addition of a node to the beginning of the list d. adding a node to the end of the list Answer: A. 23. In an array based implementation of the ADT List, what is a characteristic of the time required to access any particular element in the list? a. you have no way of knowing how long it will take b. the time required is a constant c. the time required is a function of the size of the list d. It is of order O(n2) Answer: B 24. When calling the insert or remove methods, what is an advantage for the link-based implementation of the ADT List? a. searching for that position is quicker b. takes less memory c. no need to shift data d. easier to understand Answer: C. 25. When calling the insert or remove methods, what is an disadvantage for the link-based implementation of the ADT List?

.

Chapter 9 Questions a. b. c. d.

Answer: A.

searching for that position is slower takes more memory must shift data harder to understand

26. Adding or removing an entry anywhere within a link based list requires a change of at least how many pointers? a. one b. two c. three d. four Answer: B. 27. A link based getEntry method requires how many steps to access the nth item in the list? a. n – 1 b. n c. n + 1 d. n2 Answer: B. 28. In either the link based or array based implementation of the ADT List, what is the single parameter for both the remove and getEntry methods? a. itemCount b. maxItems c. position d. ItemType Answer: C. 29. What is the last step in the insertion process for a linked implementation of the ADT List? a. Connect the new node to the linked chain by changing pointers b. Create a new node and store the new data in it c. Determine the point of insertion d. The order of these steps really doesn’t matter Answer: A. 30. What is the first step in the deletion process for a linked implementation of the ADT List? a. Return the node to the system b. Disconnect the node from the linked chain by changing pointers c. Locate the node you want to delete d. The order of these steps really doesn’t matter Answer: C.

.

Chapter 9 Questions True/False Questions 1. A pointer whose value is NULL does not point to anything.

Answer: True.

2. A newly declared pointer variable has a default value of NULL. Answer: False.

3. In C++, the programmer must explicitly deallocate memory.

Answer: True.

4. If the value of the head pointer is NULL, the linked list is empty.

Answer: True.

5.

When you design an abstract data type, you concentrate on what its operations do and how you will implement them.

Answer: False When designing an array implementation of an ADT List class, identifiers such as DEFAULT_CAPACITY, items, itemCount and maxItems are specified as private.

Answer: True 6.

In an array based implementation of the ADT List, the clear method must walk through the array and set each value to null.

Answer: False.

7.

8. A link based implementation of the ADT List does not shift items during insertion and deletion operations.

Answer: True.

9. A link based implementation of the ADT List imposes a maximum length on the list.

Answer: False.

10. Both the array based and the link based implementations of method getEntry as developed by the author should throw an exception if the parameter position is out of bounds.

Answer: True

.

Chapter 9 Questions Short Answer Questions 1. What is the difference between static and dynamic allocation?

Answer: Memory for statically allocated variables is allocated at compilation time; therefore, memory requirements for statically allocated variables are not affected by the execution of the program. Memory for dynamically allocated variables is allocated during execution time.

2. What is a memory leak?

Answer: A memory leak occurs when a memory cell remains allocated to a program, even though it is no longer accessible because no pointer to the cell exists.

Write the code segment that inserts into a linear linked list the node to which newPtr points between the two nodes pointed to by the variables prevPtr and curPtr. Answer: newNodePtr –>setNext(curPtr); prevPtr –>setNext(newNodePtr); 3.

4. Write the code segment that inserts a new node to which newPtr points at the beginning of a linear linked list.

Answer: newPtr->next = head; head = newPtr; 5. Why is an array-based implementation of a list a natural choice?

Answer: Both an array and a list identify their items by number.

6. In the array based implementation of list,why do getEntry and setEntry throw an exception?

Answer: Either of these operations could specify a position that is beyond the limits of the array (larger than DEFAULT_CAPACITY or less than 1).

7.

What strategy is used by the author to test core group of methods for a new implementation of an ADT List class?

Answer: Write stubs for the remaining methods and write a simple client program which loads the list, then walks through the list, displaying the values of the items stored and their locations.

8.

Why must the link based implementation of the ADT List not depend on a compiler generated default constructor?

Answer: It would not necessarily initialize headPtr to nullptr and itemCount to 0.

9. What high level steps are required in the link based implementation of ADT List to insert a new item?

Answer: Create a new node and store the data in it, determine the point of insertion, connect the new node to the linked chain by changing pointers.

10. What high level steps are required in the link based implementation of ADT List to delete an existing item from the list?

Answer: Locate the node you want to delete, disconnect this node from the linked chain by changing pointers, return the node to the system.

11. Why cannot the link based implementation of the ADT List use a compiler generated copy constructor?

Answer: It would copy only the data members headPtr and itemCount. It would not copy all the nodes and their contents.

12. You have chosen an array based implementation for an ADT List with size 100. You discover that occasionally this size is too small. What options do you have?

Answer: Either resize the array or use a link-based implementation.

13. For a link based implementations of the ADT List which two methods are treated as special cases?

Answer: Adding to the beginning or removing the first entry require special treatment.

.

Chapter 9 Questions 14. For a link based implementations of the ADT List which two methods require traversal of the underlying chain?

Answer: Adding or removing an entry at the end of the list.

15. Why must you use the use this sequence of statements when removing a node from a linked implementation of an ADT List? curPtr->setNext( nullptr ); delete curPtr; curPtr = nullptr ; Answer. Even though it is not part of the chain of the list, it still exists in memory and require storage space. The program would no longer be able to access this memory. This is called a memory leak.

.

Chapter 10 Questions Multiple Choice Questions 1.

Which of the following is NOT part of the human cost of developing a computer program? a. efficiency of a program b. the the readability of a program c. the modifiability of a program d. the maintainability a program Answer: a.

2.

Algorithm analysis should be independent of all of the following EXCEPT ______. a. the programming style used in the implementation of the algorithm b. the computer used to run a program which implements an algorithm c. the number of significant operations in an algorithm d. the test data used to test a program which implements an algorithm Answer: c.

An algorithm’s execution time is related to the number of ______ it requires. a. parameters b. test data sets c. data fields d. operations Answer: d.

3.

4.

Assuming a linked list of n nodes, the C++ statements Node *cur = head; while (cur != null) { cout << curr->item << endl; cur = cur->next; } // end while require ______ assignment(s). a. n b. n – 1 c. n + 1 d. 1 Answer: c.

5.

Assuming a linked list of n nodes, the C++ statements Node *cur = head; while (cur != null) { cout << curr->item << endl; cur = cur->next; } // end while require ______ comparison(s). a. n b. n – 1 c. n + 1 d. 1 Answer: c.

6.

Assuming a linked list of n nodes, the C++ statements Node *cur = head; while (cur != null) { cout << curr->item << endl; cur = cur->next; } // end while perform ______ write operations.

.

Chapter 10 Questions a. b. c. d.

Answer: a.

n n–1 n+1 1

The solution to the Towers of Hanoi problem with n disks requires 2n – 1 moves. If each move requires the same time m, the solution requires ______ time units. a. 2n – 1 b. (2n – 1) + m c. (2n – 1) / m d. (2n – 1) * m Answer: d.

7.

8.

Consider an algorithm that contains loops of this form: for (i = 1 through n) { for (j = 1 through i) { for (k = 1 through 10) { Task T } } } If task T requires t time units, the innermost loop on k requires ______ time units. a. j b. 10 c. k * t d. 10 * t Answer: d.

9.

Consider an algorithm that contains loops of this form: for (i = 1 through n ) { for (j = 1 through i) { for (k = 1 through 10) { Task T } } } If task T requires t time units, the loop on j requires ______ time units. a. 10 * t b. (10 * t) + i c. 10 * t * i d. t * i Answer: c.

10. Which of the following can be used to compare two algorithms? a. growth rates of the two algorithms b. implementations of the two algorithms c. test data used to test programs which implement the two algorithms d. computers on which programs which implement the two algorithms are run Answer: a.

11. Algorithm efficiency is typically a concern for ______. a. small problems only b. large problems only c. medium sized problems only d. problems of all sizes

.

Chapter 10 Questions Answer: b.

12. If a problem of size n requires time that is directly proportional to n, the problem is ______. a. O(1) b. O(n) c. O(n2) d. O(log2 n) Answer: b.

13. Which of the following growth-rate functions grows the fastest in value? a. 1 b. n c. n2 d. log2 n Answer: c.

14. Which of the following growth-rate functions grows the slowest in value? a. 1 b. n c. n2 d. log2 n Answer: a.

15. Which of the following growth-rate functions indicates a problem whose time requirement is constant? a. 1 b. n c. 2n d. log2 n Answer: a.

16. Which of the following growth-rate functions indicates a problem whose time requirement is independent of the size of the problem? a. 1 b. n c. 2n d. log2 n Answer: a.

17. A linear algorithm has the growth-rate function ______. a. 1 b. n c. 2n d. log2 n Answer: b.

18. A quadratic algorithm is ______. a. O(n2) b. O(n3) c. O(2n) d. O(log2 n) Answer: a.

19. An exponential algorithm is ______. a. O(n2) b. O(n3) c. O(2n) d. O(log2 n)

.

Chapter 10 Questions Answer: c.

.

Chapter 10 Questions True/False Questions 1.

The analysis of an algorithm must take into consideration the computer that will be used to run a program that implements the algorithm.

Answer: False.

2.

For a problem of size n, if Algorithm A requires time proportional to n, and Algorithm B requires time proportional to n2, B’s time requirement increases at a slower rate than A’s time requirement.

Answer: False.

3. The values of the growth-rate function O(log2 n) grow faster than the values of the growth-rate function O(n).

Answer: False.

4. Low-order terms in an algorithm’s growth-rate function can be ignored.

Answer: True.

5. Function f(n) is O( g(n) ) if f(n)>g(n) for all n>0.

Answer: False.

.

Chapter 10 Questions Short Answer Questions 1. What measurements indicate a program’s efficiency?

Answer: The amount of computer time and the amount of space that the program requires to execute.

2. The analysis of algorithms—as an area of study—provides what tools for the computer scientist?

Answer: Analysis of algorithms is the area of computer science that provides tools for contrasting the efficiency of different methods of solution.

3.

List three reasons why you should not write and run C++ programs to compare the time efficiency of algorithms.

Answer: Writing and running C++ programs to compare the time efficiency of algorithm is problematic because the results are influenced by the talent of the programmer, the speed of the computer, and the nature of the test data.

4. What does an algorithm’s growth rate measure?

Answer: An algorithm’s growth rate measures how fast an algorithm’s time requirement grows as a function of the problem size.

5. What is a growth-rate function?

Answer: A growth-rate function is a mathematical function used to indicate an algorithm’s time efficiency in terms of the size of the problem.

6. What is measured by a worst-case analysis?

Answer: Worst-case analysis provides a measure of the maximum amount of time that a given algorithm requires to solve problems of size n.

7. What is measured by an average-case analysis?

Answer: Average-case analysis provides a measure of the average amount of time that a given algorithm requires to solve problems of size n.

8.

When choosing between two algorithms, under what conditions can the efficiencies of the algorithms be ignored?

Answer: The efficiencies of the algorithms can be ignored if the problem size is always small.

.

Chapter 11 Questions Multiple Choice Questions 1.

In the worst case, a binary search is ______. a. O(n) b. O(1) c. O(log2 n) d. O(n2) Answer: c.

2.

The selection sort continues until ______ of the n items in an array have been swapped. a. n/2 b. n – 2 c. n – 1 d. n Answer: c.

3.

Given the following array: 4 15 8 3 28 21 which of the following represents the array after the second swap of the selection sort? a. 4 3 8 15 21 28 b. 4 15 8 3 21 28 c. 3 4 8 15 21 28 d. 21 4 3 8 15 28 Answer: b.

Given the fact that a selection sort of n items requires n2/2 + 5 * n/2 – 3 major operations, the selection sort is ______. a. O(1) b. O(n) c. O(n2) d. O(log2 n) Answer: c.

4.

5.

The ______ compares adjacent items and exchanges them if they are out of order. a. selection sort b. binary search c. bubble sort d. quicksort Answer: c.

6.

A bubble sort requires at most ______ passes to sort an array of n items. a. n/2 b. n – 2 c. n – 1 d. n Answer: c.

In the worst case, the insertion sort’s comparison occurs ______ times. a. n b. n – 1 c. (n – 1) / 2 d. n * (n – 1)/2 Answer: d.

7.

8.

Each merge step of the mergesort requires ______ major operations.

.

Chapter 11 Questions a. 3 * n – 1 b. 4 * n – 1 c. (n – 1)/2 d. n – 1 Answer: a.

9.

The quicksort is ______ in the worst case. a. O(n2) b. O(n3) c. O(n * log2 n) d. O(log2 n) Answer: a.

10. Select the sorting algorithm(s) that is O(n2)

a) b) c) d)

insertion sort selection sort bubble sort all three

Answer: D 11. The worst scenario for insertion sort is

a) b) c) d)

987654321 192837465 826453719 563892174

Answer: A 12. The ___ compares adjacent items and exchanges them if they are out of order.

a) selection sort b) binary search c) bubble sort d) quicksort Answer: C 13. A merge sort operation runs in:

a) b) c) d)

O(log n) time.

O(n) time.

O(n log n) time.

O(n2) time.

Answer: C

.

Chapter 11 Questions True/False Questions 1. The efficiency of the selection sort depends on the initial arrangement of the data.

Answer: False.

2. For large arrays, the insertion sort is prohibitively inefficient.

Answer: True.

3.

In a recursive mergesort, the actual sorting occurs during the recursive calls. The merge step simply puts two array segments together again.

Answer: False.

4. To sort numeric data, the radix sort treats each number as a character string.

Answer: True.

5. Insertion sort can be implemented as in-place sort.

Answer: True 6. Quick sort can be slower than insertion sort.

Answer: True

.

Chapter 11 Questions Short Answer Questions 1. What is an internal sort?

Answer: An internal sort is a sorting algorithm that requires the collection of data to fit entirely in the computer’s main memory.

2. What is an external sort?

Answer: An external sort is a sorting algorithm that is used when the collection of data will not fit in the computer’s main memory all at once, but must reside on secondary storage such as a disk.

3. What is the sort key of a record?

Answer: The sort key is the part of a record that determines the sorted order of the entire record within a collection of records. A sorting algorithm uses a sort key to order records within a collection of records.

4. In the worst case, how many comparisons does a bubble sort require?

Answer: In the worst case, the bubble sort requires n * (n – 1)/2 comparisons.

5. What is the drawback of the mergesort with respect to storage?

Answer: The mergesort requires an auxiliary array whose size equals the size of the original array. For languages, such as C++, that store the actual data items in the array, this requirement might not be acceptable in situations where storage is limited and the items are large.

6. How does the quicksort partition an array?

Answer: The quicksort partitions an array into items that are less than the pivot and those that are greater than or equal to the pivot.

7. Compare the efficiencies of the quicksort and the mergesort in the worst case.

Answer: In the worst case, the quicksort is O(n2), while the mergesort is O(n * log2 n). Thus, the quicksort is significantly slower than the mergesort in the worst case.

.

Chapter 12 Questions Multiple Choice

1. Which of the following operations was NOT included in the ADT sorted list operations? a. print the sorted list b. insert an entry into a sorted list c. remove the entry at a given position from a sorted list d. remove a given entry from a sorted list Answer: A 2. Which of the following operations from the ADT sorted list behave as they do in the ADT list? a. getPosition(anEntry) b. getLength() c. removeSorted(anEntry) d. insertSorted(newEntry) Answer: B 3. Given the following sequence of names added to an ADT sorted list: nameListPtr–>insertSorted("Tammie"); nameListPtr–>insertSorted("Brenda"); nameListPtr–>insertSorted("Sarah"); nameListPtr–>insertSorted("Tom"); nameListPtr–>insertSorted("Carlos"); What would be returned by the call nameListPtr-> getPosition(“Tammie”) a. 1 b. 3 c. 4 d. 5 Answer: C 4. In the class LinkedSortedList, which of the following items are private? a. the constructor b. isEmpty() c. getEntry(position) d. getNodeAt(position) Answer: D 5. Given a sorted list with entries in ascending order, where do you insert a new entry? a. just before the first entry that is not smaller than the new entry b. just after the first entry that is not smaller than the new entry c. just before the first entry that is not larger than the new entry d. at the end of the list Answer: A

.

Chapter 12 Questions 6. Given the following figure to the right: According to the text, what is the relationship between List A and List B? a. List A is composed of an instance of List B b. List B is composed of an instance of List A c. List A is concatenated to list B d. List B is a subset of list A Answer: B 7. When an ADT sorted list is implemented using an instance of the ADT list which is link based, what is the worst case efficiency? a. O(1) b. O(n) c. O(n2) d. O(n * log2 n) Answer: C 8. When an ADT sorted list is implemented using an instance of the ADT list which is link based, which of the following operations has worst case efficiency? a. insertSorted (newEntry) b. getEntry (position) c. clear() d. isEmpty() Answer: D 9. Given the following figure to the right: According to the text, what is the relationship between List A and List B? a. List B is a descendant of List B b. List A is a descendant of List A c. List A comes after list B d. List B is a clone of list A Answer: A 10. In the class LinkedSortedList, the method copyChain(ptr)is classified as which of the following? a. public b. private c. shared d. virtual Answer: B 11. In the array based implementation of the ADT List operation replace, what is the efficiency? a. O(n) b. O(n2) c. O(1) d. O(log n) Answer: C

.

Chapter 12 Questions 12. Which operation creates a new list and then copies the entries in the given sorted list to the new list. a. newList b. destructor c. constructor d. copy constructor Answer: D

.

Chapter 12 Questions True or False 1. One of the most frequently performed computing tasks is the maintenance of a collection of data in some specified order.

Answer: True 2. The ADT list maintains its entries in sorted order.

Answer: False 3. The ADT sorted list in the text allowed the sorted list to contain duplicate items.

Answer: True 4. A sorted list will allow you to add or replace an entry by position.

Answer: False 5. In the class LinkedSortedList, the method copyChain(ptr), is private.

Answer: True 6. The ADTs sorted list and list are completely different in their implementations.

Answer: False 7. The addition to a sorted list is an O(n) operation.

Answer: True 8. It is not possible to use the ADT list when implementing an ADT sorted list.

Answer: False 9. The copy constructor creates a new list and then copies the entries in the given sorted list to the new list.

Answer: True 10. The implementation of the sorted list using containment is both easy to write and efficient if the underlying list uses a chain of linked nodes.

Answer: False 11. An is-a relationship implies public inheritance.

Answer: True 12. According to the text most operations for the ADT list are exactly the same as the corresponding operations for the ADT sorted list.

Answer: False 13. Private inheritance enables you to use the methods of a base class without giving a client access to them.

Answer: True 14. In an ADT sorted list, the client software determines where to place an entry.

Answer: False

.

Chapter 12 Questions 15. According to the text, a chain of linked nodes provides a reasonably efficient implementation of the sorted list.

Answer: True 16. A sorted list is-a list. It is appropriate to use public inheritance.

Answer: False 17. Private inheritance does not allow you to use an instance of SortedListAsA wherever you can use an instance of LinkedList.

Answer: True

.

Chapter 12 Questions Short Answer 1. State three ways in which a sorted list may be implemented.

Answer: any three of the following array, chain of linked nodes, instance of a vector, instance of an ADT list 2. What does adding an entry to a sorted list require?

Answer: find where in the list the new entry belongs 3. Given the following sorted chain of linked nodes.

According to the text, where would you insert a new node with the string “Sue” Answer: Between “Mike” and the existing node with “Sue” 4. What pointers are needed in the method getNodeBefore from the class LinkedSortedList?

Amswer: a pointer to the current node, a pointer to the previous node.

5. Deriving a class of sorted lists from a class of lists using public inheritance is not appropriate.

What extra steps must be taken to do this?

Answer: override some methods of the list class, do not use a sorted list anywhere that a list is used.

6. Given nameListPtr points to an empty ADT sorted list. Also given the following sequence of names added to an ADT sorted list: nameListPtr–>insertSorted("Tammie"); nameListPtr–>insertSorted("Darlah"); nameListPtr–>insertSorted("Sarah"); nameListPtr–>insertSorted("Tom"); nameListPtr–>insertSorted("Carlos"); What would be returned by the call nameListPtr–>getEntry(2) Answer: Darlah 7. Given nameListPtr points to an empty ADT sorted list. Also the following sequence of method calls on this instance of the list. nameListPtr–>insertSorted("Tammie"); nameListPtr–>insertSorted("Darlah"); nameListPtr–>insertSorted("Sarah"); nameListPtr–>insertSorted("Tom"); nameListPtr–>insertSorted("Carlos"); nameListPtr->remove(“Carlos”); nameListPtr->remove(1); What would be returned by the call nameListPtr->getEntry(2); Answer: Tammie .

Chapter 12 Questions 8. What two operations have efficiency O(n) for both array-based and link-based ADT list implementations?

Answer: insert and remove 9. What two operations have efficiency O(1) for both array-based and link-based ADT sorted list implementations?

Answer: getLength() and isEmpty() 10. When using public inheritance from the ADT list to create an ADT sorted list, why were the inherited methods insert and replace overridden?

Answer: we do not want clients to be able to destroy the sorted order of our entries by inserting an item at any specific position within a sorted list.

11. When is the only time to use public inheritance?

Answer: when the two classes have an is-a relationship.

12. What advantage does private inheritance give in a non is-a relationship between two classes?

Answer: It enables you to use methods of a base class without giving a client access to them.

.

Chapter 13 Questions Multiple Choice Questions 1.

A priority queue orders its items by ______. a. position b. value c. priority value d. size Answer: c

2.

The first item to be removed from a priority queue is the item ______. a. at the front of the priority queue b. at the end the priority queue c. with the highest value d. with the highest priority value Answer: d

3.

Which data structure represents a waiting line and limits insertions to be made at the back of the data structure and limits removals to be made from the front? a. Stack. b. tree. c. Linked list d. Queue.

Answer: D 4.

Which of the following characterizes a stack? a. FIFO b. LIFO c. FILO d. LILO Answer: B 5.

Which of the following characterizes a queue? a. FIFO b. LIFO c. FILO d. LILO Answer: A 6.

Which of the following is not an ADT Queue operation as presented by the author? a. test if queue is empty b. add new entry to back of queue c. add new entry to front of queue d. get entry that was added earliest to the queue Answer: C Which of the following ADT Queue operators does not have return type specified as bool? a. isEmpty b. dequeue c. peekFront d. enqueue Answer: C 7.

8.

Which of the following ADT Queue operators has a parameter? a. isEmpty

.

Chapter 13 Questions b. c. d.

Answer: D 9.

dequeue peekFront enqueue

Given the following queue operations on an empty existing queue called nameQueue. nameQueue.enqueue(Sid) nameQueue.enqueue(Sal) nameQueue.enqueue(Sue) nameQueue.enqueue(Sam) nameQueue.dequeue() display (nameQueue.peekFront())

a. b. c. d.

What name is displayed?

Sid Sal Sue Sam Answer: B

10. Given the following queue operations on an empty existing queue called nameQueue. nameQueue.enqueue(Bob) nameQueue.enqueue(Bill) nameQueue.enqueue(Bud) nameQueue.dequeue() nameQueue.enqueue(Boo) What is now the contents of the queue (with front of the queue listed leftmost)? a. Bob, Bill, Bud b. Bob, Bud, Boo c. Bill, Bud, Boo d. Boo, Bud, Bill Answer: C 11. Given two initially empty queues, queue1 and queue2 and the following commands. queue1.enqueue(1) queue1.enqueue(2) queue2.enqueue(3) queue2.enqueue(4) queue1.dequeue() queueFront = queue2.peekFront() queue1.enqueue(queueFront) queue1.enqueue(5) queue2.dequeue() queue2.enqueue(6) What are now the contents of What is now the contents of queue1 (with front of the queue listed leftmost)? a. 2, 3, 5 b. 5, 3, 2 c. 4, 6 d. 6, 4 Answer: A 12. Given two initially empty queues, queue1 and queue2 and the following commands. queue1.enqueue(1) queue1.enqueue(2)

.

Chapter 13 Questions queue2.enqueue(3) queue1.enqueue(4) queue1.dequeue() queueFront = queue1.peekFront() queue1.enqueue(queueFront) queue2.enqueue(5) queue1.dequeue() queue2.enqueue(7) What is the sum of the contents of queue2? a. 4 b. 15 c. 19 d. none of these Answer: B 13. According to the text, the first step in simulating a system is to do what? a. write a computer program b. time events with a stopwatch c. construct a mathematical model d. hire a lawyer Answer: C 14. An algorithm performing simulation of an oft repeated cycle, measuring the times and generating statistics is called what? a. customer loop b. timing loop c. statistical loop d. event loop Answer: D 15. Which of the following are not position-oriented ADTs? a. bag b. stack c. list d. queue Answer: A 16. Which of the following would be an example of a value-oriented ADT? a. bag b. priority queue c. list d. stack Answer: B 17. For a stack, the push method places a new item onto the stack. What method for the queue would do a similar task? a. dequeue b. isEmpty c. enqueue d. peek Answer: C 18. For a queue, the dequeue removes the first item. What method for the stack is used to remove the appropriate item?

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Chapter 13 Questions a. peek b. poke c. enqueue d. pop Answer: D 19. Which ADT would be best use to model the customers at a bakery who take numbers to mark their turn? a. queue b. stack c. list d. bag Answer: A 20. You are writing a simple word processor. What ADT would be best to use which would allow the typist to correct typing errors by using the Backspace key. a. queue b. stack c. list d. sorted list Answer: B 21. In an event driven simulation, how is simulated time advanced? a. by a single time unit b. by a stop watch c. advanced to the time of the next event d. by a calendar Answer: C 22. You wish to model who gets to land first as airplanes arrive at a busy airport. What kind of simulation would this be? a. time-driven simulation b. customer-driven simulation c. a sorted list d. event-driven simulation Answer: D 23. Lining up to buy a movie ticket or being put on hold by a computerized phone system are both examples of what type of ADT? a. queue b. stack c. list d. sorted list Answer: A 24. Which of the following tasks would be a good application of the ADT Queue? a. generating random numbers for a game b. reading a string of characters c. keeping a grocery list d. parsing a mathematical expression such as (9 + 5) * 7^ 2 Answer : B 25. What ADT would be used along with a queue to determine if a string is a palindrome? a. list b. sorted list c. stack d. priority queue

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Chapter 13 Questions Answer: C 26. You are making a “to do” list for this week. You brainstorm all the things which need your attention, then you arrange them from most important to least. You have just used what kind of ADT? a. list b. sorted list c. stack d. priority queue Answer: D 27. An event list contains all future arrival events and what else? a. departure events b. event loops c. clock time d. externally generated events Answer: A 28. Which of the following is not a similarity between a stack and a queue as described by the text? a. both have an isEmpty method b. both can retrieve an item from any position c. both can insert an entry at one end of the structure d. both can retrieve an entry from one end of the structure Answer: B 29. A large corporation is facing financial troubles and finds that they must do a reduction in force (RIF). The people who were most recently hired must be let go. This is an example of which ADT? a. bag b. list c. stack d. queue Answer: C

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Chapter 13 Questions True/False Questions

1. Queue is a First-in-Last-out data structure. That is, the last element inserted into a queue is removed first.

Answer: False 2. Queues are important in simulating and analyzing the behavior of complex systems.

Answer: True 3.

It is possible to use a queue in conjunction with a stack to reverse the order of occurrences of a sequence of items.

Answer: True 4.

If you create a queue of assignments and access the queue by due dates of the assignments this is called a priority queue.

Answer: True 5. The goal of simulation is to generate reports of transactions.

Answer: False 6. An even driven simulation simulates the ticking of a clock.

Answer: False 7. The ADT bag does not order its entries.

Answer: True 8. The isEmpty function for a stack does a much different task than the same function for a queue.

Answer: False 9.

You are put on hold when you call customer service. The automated system tells you an approximation of how long a wait you will have. This is most likely being modeled by a queue.

Answer: True 10. You are watching old reruns of M.A.S.H. You notice that when a group of casualties arrive, the doctors and nurses are, in effect using an ADT stack to determine who goes to the operating room first.

Answer: False

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Chapter 13 Questions Short Answer Questions 1. Describe how you would use a queue and a stack to evaluate if a string is a palindrome.

Answer: As you traverse a string from left to right, you can add each character to both a queue and a stack. Now pop characters off the stack and dequeue characters off the queue. If each pair is the same, you have a palindrome.

Give an example the difference between externally and internally generated events in an event-driven simulation.

Answer: Bank customers arriving are externally generated events. Bank customers completing their transactions and departing are internally generated events.

2.

3. In a simulation, what does an event list contain?

Answer: An event list contains all future arrival events and departure events.

4. What queues were required for the bank simulation algorithm as described in the text?

Answer: A queue for the arrivals for the customers and a queue for the events, arrivals and departures.

5. Describe the similarities of the queue and the stack.

Answer: Both keep items in order. Both have methods for getting the length, inserting, removing, and looking at entries in the structure (top or front) 6. List differences between the list as opposed to the stack or queue.

Answer: List insert can place an item anywhere in the structure, stacks and queues can have items added only at one end of the structure. Methods pop and dequeue can remove only from one end or the other, the list remove can do so anywhere in the list. Similarly with the getEntry, it can do so anywhere in the structure but peek and peekFront can access only specific locations.

7. What kind of operations would be required for accessing items in a priority queue?

Answer: It would require operations to place items in the queue according to both priority and arrival sequence. It would also need operations to retrieve or remove the item with the highest priority and (if the same high priority) at the front of the queue.

8.

Give some examples where the importance of an object depends on criteria other than when it is placed into a container. What is the best ADT choice for that container?

Answer: Examples include: the severity of medical emergency when a person comes to the ER, the importance of a computer task as to which program a multitasking operating system lets go first, VIP’s get to meet the president a lot quicker than a tourist, people with reservations or important regular customers get seats at a restaurant quicker than a walk in customer.

9. Give a definition of a priority queue.

Answer: A finite number of objects, not necessarily distinct, having the same data type and ordered by priority.

10. Describe the difference between a queue and a priority queue.

Answer: The queue has the data ordered by when they were added. The priority queue data items are ordered by some other value which specifies the priority (date, importance, etc.) When an item is removed from a queue, it is the item that was the first one entered by time. When an item is removed from a priority queue, it is the one with the highest priority (and first entered, if the same priority).

11. Give some examples of a applications in computer science where a queue useful.

Answer: A queue is used when sending characters from a word processor to the printer. When multiple documents from multiple users is sent to a single printer, they are placed into a queue.

12. Describe how tracking your assignments can be accomplished by a special ADT.

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Chapter 13 Questions Answer: You would use a priority queue. You list all assignments and order them by date due. Alternatively you make an estimate of how many hours each would take and if two assignments are due on the same day but one would require 5 hours and the other only 30 minutes, you start work on the longer assignment sooner before it is due.

13. What is the goal of a computer simulation?

Answer: Generally, the goal of a simulation is to generate statistics that summarize the performance of an existing system or to predict the performance of a proposed system. Note that the goal is to reflect the longterm average behavior of the system rather than to predict occurrences of specific events.

14. We are simulating customers arriving at a bank and their transactions being processed. How do we determine when and how long these events occur?

Answer: We study real world systems (such as the bank) and model events using techniques from probability theory.

This statistical information is incorporated into the mathematical model of the system. Events are generated in a way that reflects the real world.

15. Given two initially empty queues, queue1 and queue2 and the following commands. queue1.enqueue(4) queue1.enqueue(3) queue2.enqueue(7) queue1.enqueue(6) queue1.dequeue() queue1.enqueue(queue2.peekFront()) queue2.enqueue(queue1.peekFront()) queue1.dequeue() queue2.enqueue(7) List the contents of both queues with the front of the queue leftmost.

Answer: Q1 = 6, 7

Q2 = 7, 3, 7

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Chapter 14 Questions Multiple Choice 1. Which of the following is a private element of the class ListQueue? a. listPtr b. isEmpty() c. peekFront() d. enqueue(const ItemType& newEntry) Answer: A 2. Which of the following methods from ListQueue throws an exception? a. isEmpty() b. peekFront() c. ListQueue() d. dequeue() Answer: B 3. In the class ListQueue, which method calls the list method insert? a. isEmpty() b. dequeue() c. enqueue(const ItemType& newEntry) d. the copy constructor Amswer: C 4. In the class ListQueue, which method calls the list method remove? a. isEmpty() b. dequeue() c. enqueue(const ItemType& newEntry) d. the copy constructor Answer: B 5. In the class ListQueue, which method besides isEmpty calls the isEmpty method from the list class? a. listPtr b. isEmpty() c. peekFront() d. enqueue(const ItemType& newEntry) Answer: C 6. Given the following diagram, a chain of linked nodes with head and tail pointers:

How does this type of a linked list help us to implement a queue? a. able to traverse the list from back to front b. able to easily delete the node at the back/end of the chain

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Chapter 14 Questions c. able to keep a sorted chain d. able to easily add a node to the back/end of the chain Answer: D 7. In class LinkedQueue, where does neNodePtr point? a. the back or end of the chain b. the front or beginning of the chain c. nullPtr d. the next element of the queue Answer: A 8. In the class LinkedQueue, what must the peekFront method do before returning the value at the front of the queue? a. traverse the chain b. check that the queue is not empty c. remove the node at the beginning of the chain d. establish a pointer to the beginning of the chain Answer: B 9. What would be the purpose of the following lines of code? back = (back + 1) % DEFAULT_CAPACITY; items[back] = newEntry; a. enables a circular linked list implementation of a queue b. eliminates rightward drift c. enables a circular array implementation of a queue d. keeps a linked list from running out of memory Answer: C 10. Which of the following elements of ArrayQueue is not private? a. back b. count c. front d. isEmpty() Answer: D 11. How does the isEmpty method of ArrayQueue class return the proper value? a. return count == 0; b. return front != back c. return front / back == 0 d. return count < DEFAULT_CAPACITY Answer: A 12. The text defined a class SL_PriorityQueue. What command was used to accomplish the enqueue method? a. insert(newEntry); b. insertSorted(newEntry); c. push(newEntry); d. addItem(newEntry); Answer: B

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Chapter 14 Questions True or False 1. Both stacks and queues can have either an array-based or a link-based implementation.

Answer: True 2. It is not possible to use an implementation of the ADT list to define a class of queues.

Answer: False 3. In the implementation of class ListQueue, the constructor creates a new instance of a list.

Omitting this step leads to incorrect execution instead of a syntax error.

Answer: True 4. In the implementation of class ListQueue, when the destructor is called, the list’s destructor is not called.

Answer: False 5. A linear linked chain can represent a queue.

Answer: True 6. If you use a linear chain with only a head pointer to implement a queue, the enqueue operation will have efficiency O(1).

Answer: False 7. In the class LinkedQueue, the addition of an item to an empty queue is treated as a special case.

Answer: True 8. A circular linked chain cannot represent a queue.

Answer: False 9. The nodes in a circular chain have next pointers that never contain nullptr.

Answer: True 10. Shifting to avoid rightward drift works well and is efficient.

Answer: False 11. A circular array eliminates rightward drift.

Answer: True 12. Using a front and back pointer in a circular array will indicate whether a queue is empty or full.

Answer: False 13. Using the ADT list to represent a queue is not as efficient as using a linked chain directly.

Answer: True 14. It is poor design to use a sorted list to contain the entries of a priority queue.

Answer: False 15. The enqueue and dequeue operations for a queue require efficient access to both ends of the queue.

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Chapter 14 Questions Answer: True 16. If you use a circular array to implement a queue, you must be able to distinguish between the queue-full and queue-empty conditions.

Answer: True

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Chapter 14 Questions Short Answer 1. What is the disadvantage stated by the text for defining a class of queues quickly using a class of lists?

Answer: The result is not as time efficient as possible.

2. Given the figure at the right: What does this represent?

Answer: an implementation of a queue which stores its entries in a list.

3. In the implementation of class ListQueue, why does the destructor have an empty body?

Answer: The list’s destructor will be invoked?

4. Consider implementing a queue with a linked-list. How do we improve the efficiency of adding a new node to the end of a chain?

Answer: use a tail pointer to reference the end of the chain 5. Given the diagram below at the right.

What does this represent?

Answer: circular chain of linked nodes with one external pointer 6. If you use a circular chain that has only a tail pointer, how do you access the data in the first node?

Answer: follow the link from the back/end pointer to the front of the chain.

7. What strategy results in the phenomenon of “rightward drift”?

Answer: implementing a queue in an array and incrementing the tail and head after a sequence of additions and removals, items in the queue will drift toward the end of the array, eventually making the array seem full, even if the queue has only a few items 8. Given the diagram to the right: What concept concerning queues does this demonstrate?

Answer: A circular array as an implementation of a queue.

9. If you are using a circular queue, how can you detect whether a queue is full or empty?

Answer: keep a count of queue items 10. What is a pro and a con of using the ADT list to represent a queue?

Answer: It is simpler to write, but it is not as efficient as using a linked chain.

11. Name two ADT structures which can be used to contain the entries of a priority queue.

Answer: any two of the following … array, chain of linked nodes, sorted list, ADT heap

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Chapter 15 Questions

Multiple Choice Questions 1.

The ADT ______ is value-oriented. a. list b. sorted list c. stack d. queue e. binary tree Answer: b.

2.

The ADT stack manages an association between data items and the ______ of the data items. a. names b. values c. sizes d. positions Answer: d.

3.

The operations of the ADT sorted list are based upon the ______ of data items. a. names b. values c. sizes d. positions Answer: b.

4.

The ______ is a position-oriented ADT that is not linear. a. sorted list b. queue c. binary tree d. list Answer: c.

5.

Which one of the following ADTs is position-oriented? a. binary tree b. sorted list c. table d. priority queue Answer: a.

6.

The node of a tree that has no parent is called a(n) ______. a. edge b. root c. leaf d. vertex Answer: b.

7.

The lines between the nodes of a tree are called ______. a. branches b. edges c. arches d. subtrees Answer: b.

8.

The node that is directly above node n in a tree is called the ______ of node n. a. root b. leaf

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Chapter 15 Questions c. parent d. child Answer: c.

9.

A node directly below node n in a tree is called a ______ of node n. a. root b. leaf c. parent d. child Answer: d.

10. In a tree, the children of the same parent are called ______. a. leafs b. siblings c. roots d. contemporaries Answer: b.

11. Each node in a tree has ______. a. exactly one parent b. at most one parent c. exactly one leaf d. at most two leaves Answer: b.

12. A node on the path from the root to node n is a(n) ______ of node n. a. ancestor b. descendant c. subtree d. leaf Answer: b.

13. A descendant of node n is a node on a path from node n to ______. a. the root b. a leaf c. a sibling of node n d. a child of node n Answer: b.

14. A subtree of node n is a subtree rooted at ______. a. node n b. the parent of node n c. a child of node n d. a sibling of node n Answer: a.

15. Each node in a binary tree has ______. a. exactly one child b. at most one child c. exactly two children d. at most two children Answer: d.

16. The ______ of a tree is the number of nodes on the longest path from the root to a leaf. a. height b. length

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Chapter 15 Questions c. depth d. balance Answer: a.

17. In a ______ of height h, all nodes that are at a level less than h have two children each. a. general tree b. binary tree c. full binary tree d. complete binary tree Answer: c.

18. A ______ of height h is full down to level h – 1, with level h filled in from left to right. a. full binary tree b. complete binary tree c. balanced binary tree d. general tree Answer: b.

19. In ______, the left and right subtrees of any node have heights that differ by at most 1. a. all trees b. all binary tress c. n-ary trees d. balanced binary trees Answer: d.

20. Which of the following is NOT a property of a complete binary tree of height h? a. all nodes at level h – 2 and above have two children each b. when a node at level h – 1 has children, all nodes to its left at the same level have two children each c. when a node at level h – 1 has one child, it is a left child d. all leaves are at level h Answer: d.

21. The traversal of a binary tree is ______. a. O(n) b. O(1) c. O(n2) d. O(log2 n) Answer: a.

22. Any data element within a record of a binary search tree is called a ______. a. field b. tree c. collection d. key Answer: a.

23. The maximum number of comparisons for a retrieval operation in a binary search tree is the ______. a. length of the tree b. height of the tree c. number of nodes in the tree d. number of leaves in the tree Answer: b.

24. The maximum height of a binary tree of n nodes is ______. a. n b. n / 2

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Chapter 15 Questions c. (n / 2) – 2 d. log2(n + 1) Answer: a.

25. The minimum height of a binary tree of n nodes is ______. a. n b. n / 2 c. (n / 2) – 2 d. log2(n + 1) Answer: d.

26. Locating a particular item in a binary search tree of n nodes requires at most ______ comparisons. a. n b. n / 2 c. (n / 2) – 2 d. log2(n + 1) Answer: a.

27. Locating a particular item in a balanced binary search tree of n nodes requires at most ______ comparisons. a. n b. n / 2 c. (n / 2) – 2 d. log2(n + 1) Answer: d.

28. A full binary tree whose height is 4 has ______ nodes. a. 7 b. 8 c. 15 d. 31 Answer: c.

29. The post order traversal of the following tree is a. b. c. d.

1, 2, 3, 4, 5, 6, 7, 8, 9 6, 2, 1, 4, 3, 5, 8, 7, 9 6, 2, 8, 1, 4, 7, 9, 3, 5 1, 3, 5, 4, 2, 7, 9, 8, 6

Answer: D

30. Each node in a binary tree has ______. a. b. c. d.

exactly one child at most one child exactly two children at most two children

Answer: D

31. The maximum number of comparisons for a retrieval operation in a binary search tree is the ______. a. length of the tree b. height of the tree c. number of nodes in the tree

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Chapter 15 Questions d. number of leaves in the tree Answer: B

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Chapter 15 Questions True/False Questions 1. The ADT queue is value-oriented.

Answer: False.

2. The ADT binary tree is position-oriented.

Answer: True.

3. The ADT binary search tree is value-oriented.

Answer: True.

4. All trees are hierarchical in nature.

Answer: True.

5. The root of a tree has one parent.

Answer: False.

6. A binary tree cannot be empty.

Answer: False.

7. A tree whose height is h has its root at level h.

Answer: False.

8. An inorder traversal visits a node before it traverses either of the node’s subtrees.

Answer: False.

9. A complete binary tree with n nodes has a height of log2(n + 1).

Answer: True.

11. The height of a binary search tree is sensitive to the order in which items are inserted into the tree.

Answer: True.

12. A balanced binary search tree has the minimum height possible for the tree.

Answer: True.

13. The in order traversal is only applicable to binary trees.

Answer: True

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Chapter 15 Questions Short Answer Questions 1. What are the three general categories of data management operations?

Answer: The three general categories are • Operations that insert data into a data collection • Operations that delete data from a data collection • Operations that ask questions about the data in a data collection 2. List three position-oriented ADTs. Answer: Position-oriented ADTs include the ADT list, the ADT queue, the ADT stack, and the ADT binary tree.

3. Define the root of a tree.

Answer: The root of a tree is the only node in the tree with no parent.

4. Define a leaf of a tree.

Answer: A leaf of a tree is a node in the tree that has no children.

5. What is a subtree?

Answer: A subtree is any node in a tree together with all of its descendants.

6. What are the characteristics of a binary tree?

Answer: A binary tree is a set of nodes that is either empty or partitioned into a root node and one or two subsets that are binary subtrees of the root. Each node has at most two children, the left child and the right child.

7. Define the left child of node n in a binary tree.

Answer: The left child of node n in a binary tree is the node directly below and to the left of node n.

8. What are the three properties of each node n in a binary search tree?

Answer: The three properties of each node n in a binary search tree are: • n’s value is greater than all values in its left subtree T L • n’s value is less than all values in its right subtree T R • both TL and TR are binary search trees 9. In what order does a preorder traversal visit a node and its subtrees?

Answer: A preorder traversal visits a node, then traverses the node’s left subtree, and then traverses the node’s right subtree.

10. In what order does an inorder traversal visit a node and its subtrees?

Answer: An inorder traversal traverses a node’s left subtree, then visits the node, and then traverses the node’s right subtree.

11. In what order does a postorder traversal visit a node and its subtrees?

Answer: A postorder traversal traverses a node’s left subtree, then traverses the node’s right subtree, and then visits the node.

12. What is a search key?

Answer: A search key is the part of a record that identifies it within a collection of records. A search algorithm uses a search key to locate a record within a collection of records.

13. Define an n-ary tree.

Answer: An n-ary tree is a generalization of a binary tree. Each of its nodes each can have no more than n children.

14. State the formal definition of a “general tree” Answer: A general tree is a set T of one or more nodes such that T is partitioned into disjoint subsets: a single node (the root) and sets that are general trees, called subtrees of the root.

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Chapter 15 Questions 15. Given the following tree:

List the preorder transversal of the tree.

Answer: 60, 20, 10, 40, 30, 50, 70

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Chapter 16 Questions Multiple Choice 1. What is the first step in implementing a tree? a. choose a data structure to represent its nodes b. determine the type of item to be stored in the tree c. determine the height of the tree d. determine how many items will be in the tree Answer: A 2. Consider an array-based representation of a tree and a variable called root as the index to the tree’s root node. What value does the text suggest to assign to root if the tree is empty? a. 0 b. -1 c. 1 d. nullptr Answer: B 3. In an array-based representation of a tree, what keeps track of available nodes? a. the variable emptyCount b. the variable nextAvailable c. the free list d. the node list Answer: C 4. What do you do if you remove a node from a tree in an array-based implementation? a. assign it to nullPtr b. nothing, leave it as is, just don’t link anything to it c. remove it from the array d. add it to the free list Answer: D 5. In the class BinaryNode, which of the following methods are specified as type bool? a. isLeaf b. setItem c. setLeftChildPtr d. getLeftChildPtr Answer: A 6. In the class BinaryNode, what value is stored in rootPtr if the tree is empty? a. 0 b. -1 c. 1 d. nullptr Answer: D

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Chapter 16 Questions 7. In the class BinaryNode, if the tree is not empty, what points to the root’s left child? a. getLeftHildPtr() b. rootPtr->getLeftChildPtr() c. getLeftChildPtr()-> rootPtr d. leftChildPtr Answer: B 8. What overladed operator did the class BinaryNodeTree have specified in the text? a. less than b. not c. assignment d. plus (concatenation) Answer: C 9. To copy a tree, traverse it in __________ and add each data item visited to a new node. a. inorder b. postorder c. reorder d. preorder Answer: D 10. What is the classification of the method getHeightHelper? a. protected b. private c. public d. restricted Answer: A 11.

Given the following code from BinaryNodeTree

template<class ItemType> bool BinaryNodeTree<ItemType>::________(const ItemType& newData) { auto newNodePtr = std::make_shared<BinaryNode<ItemType>>(newData); rootPtr = balancedAdd(rootPtr, newNodePtr); return true; } // end add What is the name of this method? a. getHeight b. add c. remove d. getEntry Answer: B

.

Chapter 16 Questions

12. In the class BinaryNodeTree, the protected method inorder has a parameter visit. What is the specification for this parameter? a. virtual b. value c. reference d. dummy Answer: C 13. To save a binary search tree in a file and then restore it to its original shape, what type of traversal should be used? a. postorder b. inorder c. reorder d. preorder Answer: D 14. To remove a leaf in a binary search tree, what must be done? a. set the pointer in the leaf’s parent to nullptr b. set the pointer in the leaf to nullptr c. set the pointer in the root to nullptr d. delete the data from the leaf Answer: A 15. If node N is being removed from a binary search tree and has a left child, what must be done if P is the parent of N? a. let the left child of N adopt P b. let P adopt the left child of N c. store the data of the left child of N in N d. store the data of N in P Answer: B 16. If a file contains items in a specified order, how must they be added to put them into a binary search tree in that same order? a. use the method addInOrder b. use the method inOrderAdd c. use the method add d. use the method reOrderAdd Answer: C 17. What efficiency is the tree sort in the average case? a. O(n) b. O(log2 n) c. O(n2) d. O(n * log n) Answer: D .

Chapter 16 Questions

.

Chapter 16 Questions True or False 1. According to the text, it is natural to make each node an object.

Answer: True 2. In an array-based implementation of a binary tree, the data member free is the index of the index of the first node in the free list. Therefore the next available node will always be at index free + 1.

Answer: False 3. When a node is removed from a tree and returned to the free list, it could be anywhere in the array.

Answer: True 4. According to the text, an array-based implementation of a binary tree is much less attractive when the tree is complete.

Answer: False 5. If you use an array-based implementation of a complete binary tree, you must be sure that the tree remains complete as a result of additions or removals.

Answer: True 6. The class BinaryNodeTree had only the default constructor.

Answer: False 7. For class BinaryNodeTree, the copy constructor and the destructor implicitly use traversal.

Answer: True 8. For class BinaryNodeTree, the copy constructor and the destructor each call a recursive method.

Answer: True 9. The add method of BinaryNodeTree concatenates two trees.

Answer: False 10. The add method of BinaryNodeTree does not indicate where that new data should be in the tree.

Answer: True 11. In the class BinaryNodeTree, the public traversal methods each call a protected method that performs the actual recursion.

Answer: True 12. A reference parameter in a protected method does not allow the client code to modify the parameter.

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Chapter 16 Questions Answer: False 13. In the class BinaryNodeTree, the methods that use the parameter visit can modify the tree’s data, but not its structure.

Answer: True 14. A binary search tree is a binary tree.

Answer: True 15. The postorder traversal of a binary search tree will visit the tree’s data items in sorted order.

Answer: False 16. Making methods protected enables a derived class to use them directly Answer: True 17. A balanced binary search tree decreases the efficiency of the ADT operations.

Answer: False 18. This is a tree of minimum height that is not complete.

Answer: True

19. The traversals of a binary search tree differ from the traversals of a binary tree.

Answer: False 20. A full tree with exactly n = 2h − 1 nodes for some height h has the exact middle of the data items in its root.

Answer: True

.

Chapter 16 Questions 21. Short Answer 1. What must each node of a tree contain?

Answer: data and pointers to the node’s children 2. Name two of the items in a TreeNode classified as private.

Answer: any two of the following item, leftChild, rightChild 3. What does a free list keep track of?

Answer: available nodes 4. In an array-based implementation of a binary tree, what is stored in leftChild or rightChid if the node has no child?

Answer: -1 5. Given the binary tree of names at the right. In the array tree below fill in the left and right child fields.

0 1 2 3 4 5

item Jose Deepak Quang Anton Elisa Mia

leftChild

rightChild

Answer:

6. In the class BinaryNode, name two void methods that are public.

Answer: any two of setItem, setLeftChildPtr, setRightChildPtr 7. For the class BinaryNodeTree, name two ways in which the constructors enable a client to define binary trees.

.

Chapter 16 Questions Answer: any two of the following an empty tree, from data for its root, which is the only node, from data for its root and from its two subtrees.

8. What kind of traversal does BinaryNodeTree use in the copyTree method?

Answer: recursive preorder (should have both words, recursive and preorder) 9. What kind of traversal does BinaryNodeTree use in the destroyTree method?

Answer: recursive postorder (must have both words, recursive and postorder) 10. Given the diagram of a binary tree to the right. Draw the next node which would be placed by the method add in BinaryNodeTree.

Answer:

11. Given the binary search tree (based on the names) to the right.

Where would the node with the the name Kody be added?

Answer: as the left child of Mia 12. Describe the three cases for the node N containing an item to be removed Answer: N is a leaf, N has only one child, N has two children

.

Chapter 17 Questions Multiple Choice Questions 1.

A heap whose root contains the item with the largest search key is called a ______. a. minheap b. maxheap c. complete heap d. binary heap Answer: b.

2.

A heap whose root contains the item with the smallest search key is called a ______. a. minheap b. maxheap c. complete heap d. binary heap Answer: a.

3.

A heap is a ______. a. general tree b. table c. full binary tree d. complete binary tree Answer: d.

4.

A semiheap is a ______. a. table b. complete binary tree c. general tree d. full binary tree Answer: b.

5. In an array-based implementation of a heap, the number of array items that must be swapped to transform a semiheap of n nodes into a heap is ______. a. n b. n + 1 c. log2 n d. log2 (n + 1) Answer: d.

In an array-based implementation of a heap, the remove operation is ______. a. O(1) b. O(n) c. O(n 2) d. O(log n) Answer: d.

6.

In an array-based implementation of a heap, the parent of the node in items[i] is always stored in ______. a. items[i/2] b. items[(i-1)/2] c. items[i-2] d. items[(i-2)/2] Answer: b.

7.

8.

In an array-based implementation of a heap, the add operation is ______. a. O(1) b. O(n) c. O(n 2) d. O(log n)

.

Chapter 17 Questions Answer: d.

9.

The heapsort is ______ in the worst case. a. O(n) b. O(log n) c. O(n * log n) d. O(n2) Answer: c.

10. The heapsort is ______ in the average case. a. O(1) b. O(n) c. O(log n) d. O(n * log n) Answer: d.

11. Which of the following is true about the heapsort? a. the heapsort does not require a second array b. the heapsort is more efficient than the mergesort in the worst case c. the heapsort is more efficient than the mergesort in the average case d. the heapsort is better than the quicksort in the average case Answer: a.

12. Since a heap is a complete binary tree, what would be an efficient basis for its implementation? a. pointer based b. array based c. a bag d. a set-based Answer: b

.

Chapter 17 Questions True/False Questions 1. In a maxheap, the root contains a search key greater than or equal to the search key in each of its children.

Answer: True.

2. In a heap, the search keys of the children of a particular node have no relationship to each other.

Answer: True.

3. The merge sort is more efficient than the heap sort in the worst case.

Answer: False.

.

Chapter 17 Questions Short Answer Questions

1. What are the two main differences between a heap and a binary search tree?

Answer: First, while a binary search tree can be viewed as being sorted, a heap is ordered in a much weaker sense.

Second, while binary search trees come in many different shapes, heaps are always complete binary trees.

2. What is one strategy to transform a semiheap into a heap?

Answer: One strategy allows the item in the root to trickle down the tree until it reaches a node in which it will not be out of place. If the root has a smaller search key than the larger of the search keys in its children, swap the item in the root with that of the larger child.

3. What does the priority value in a priority queue correspond to in a heap?

Answer: The priority value of an item in a priority queue corresponds to a heap item’s search key.

4.

What is the major advantage that a heap implementation of a priority queue has over a binary search tree implementation?

Answer: The major advantage of the heap implementation is that a heap is always balanced. This is not the case with a binary search tree, which degrades the binary search tree’s efficiency.

5. What must be done to remove the value in the root of a heap?

Answer: You must first replace the value with the value in the last node of the heap.

This step likely results in a semiheap. After deleting the last node, you convert the semiheap to a heap by a trickle-down step.

.

Chapter 18 Questions Multiple Choice 1. The ADT dictionary is appropriate for problems that must manage data by a. value b. order c. priority d. importance Answer: A 2. What does the ADT dictionary use to identify its entries? a. it’s position in the list b. a search key c. its priority d. what group it belongs to Answer: B 3. Which of the following is not an ADT dictionary operation? a. add a new entry b. retrieve an entry c. sort the entries d. traverse the entries in sorted search-key order Answer: C 4. Which of the following is the better choice when attempting to add a new entry to a dictionary where the search key already exists? a. replace the existing entry with a new entry b. crash the program c. throw an exception d. deny the attempt Answer: D 5. In the header file for the class ArrayDictionary, the text declares which of the following methods as private? a. destroyDictionary() b. isEmpty() c. getNumberOfEntries() d. clear() Answer: A 6. In the class ArrayDictionary declared by the text, which of the following methods bears the responsibility for keeping the array items sorted? a. remove b. add c. getValue d. traverse Answer: B 7. According to the text, for the ADT dictionary, in which of the following situations would a sorted array-based implementation be appropriate for frequent retrievals? a. when the maximum size is unknown

.

Chapter 18 Questions b. when the maximum size is known c. when you have duplicate search keys d. when search keys are all similar.

Answer: C 8. According to the text, for the ADT dictionary, what implementation should be used when you do not know the maximum size of the dictionary? a. link-based b. array-based c. max-heap d. binary search tree Answer: D 9. According to the text, for the ADT dictionary, a sorted array-based implementation will shift data during what two operations? a. additions and removals b. additions and traversals c. removals and traversals d. searches and gets Answer: A 10. Which of the following dictionary operations has efficiency O(n) no matter what implementation if the ADT dictionary is chosen? a. retrieval b. traversal c. removal d. addition Answer: B 11. What is the implementation of the ADT dictionary which has efficiency O(log n) for addition? a. unsorted link-based b. sorted array-based c. binary search tree d. sorted link-based Answer: C 12. What is the implementation of the ADT dictionary which has efficiency O(1) for addition? a. sorted link-based b. sorted array-based c. binary search tree d. unsorted link-based Answer: D 13. What kind of function tells you where a dictionary entry is currently or will be placed if it is new? a. hash function b. logarithmic function c. interrogatory function d. big O function Answer: A

.

Chapter 18 Questions 14. What is it called when a hash function maps two or more search keys into the same integer a. an accident b. a collision c. a perfect hash function d. an exception Answer: B 15. When you begin at the hash location and search the dictionary sequentially, this is called what? a. closed addressing b. Horner’s rule c. linear probing d. inverse probing Answer: C 16. The process of enlarging a hash table and computing new hash indices for its contents is called a. re-probing b. de-hashing c. inverse hashing d. re-hashing Answer: D 17. You define a hash table so that each location table[i] is itself an array. This array is referred to as a(n) a. bucket b. bracket c. closet d. shelf Answer: A

.

Chapter 18 Questions True or False 1. To make an intelligent choice among various possible dictionary implementations, you must analyze the efficiency with wich each supports the dictionary operations Answer: True 2. The getValue(searchKey) method for an ADT dictionary retrieves the specified search key for a given value.

Answer: False 3. The client code should not be able to modify an entry’s search key once that entry is in the dictionary.

Answer: True 4. An ADT dictionary should never allow duplicate search keys Answer: False 5. The traverse method visits all dictionary entries.

Answer: True 6. A dictionary must store and form an association between search key and data value only for a sorted version of the dictionary, not for unsorted.

Answer: False 7. A linear link-based implementation of the ADT dictionary does not need to shift data for an add or a remove operation.

Answer: True 8. A linear link-based implementation of the ADT dictionary supports addition and removel operations more efficiently than an array-based implementation.

Answer: False 9. A binary search tree implementation of the ADT dictionary is nonlinear.

Answer: True 10. In the ArrayDictionary class, we must sort the items each time traverse is called.

Answer: False 11. The binary search tree implementation of the ADT dictionary has a binary search tree as a data member.

Answer: True 12. The add method for the template for TreeDictionary presented in the text does not allow for duplicate entries.

Answer: False 13. It is important to know both what operations are needed for a given application of an ADT dictionary and how often each operation is required.

Answer: True

.

Chapter 18 Questions 14. A sorted array-based implementation of the ADT dictionary cannot use a binary search.

Answer: False 15. A binary search is impractical with a link-based implementation of the ADT dictionary.

Answer: True 16. An implementation of the ADT dictionary using a binary search tree is a poor choice for retrieval dominate applications.

Answer: False 17. Because linear implementations are easy to understand conceptually they are appropriate for dictionaries that will only contain a small number of entries.

Answer: True 18. According to the text, if the size of a problem is small, the difference in efficiency among possible solutions is likely insignificant.

Answer: True 19. If the size of a dictionary is small, a linear implementation is inadequate and difficult to understand.

Answer: False 20. A perfect hash function maps each search key into a unique location of the hash table.

Answer: True 21. It is insufficient for hash functions to operate only on integers.

Answer: False 22. Digit selection does not distribute entries in the hash table.

Answer: True 23. Quadratic probing causes no clustering at all.

Answer: False 24. Double hashing drastically reduces clustering.

Answer: True 25. With separate chaining, the size of the dictionary is dynamic and can exceed the size of the hash table.

Answer: True 26. On average, quadratic probing and double hashing require more comparisons than linear probing.

Answer: False 27. Dictionary traversal is inefficient when using hashing.

Answer: True

.

Chapter 18 Questions Short Answer 1. Consider sorting a group of people based on their zip code. This criteria is known as a(n) ________________.

Answer: search key 2. What are two other names for the ADT dictionary?

Answer: map or table 3. An entry in an ADT dictionary is sometimes known as a(n) _________________ pair.

Answer: key-value 4. What are two possible things that could be done if a new entry’s search key already exists in the dictionary?

Answer: any two of … deny the attempt, ignore the attempt, replace the existing entry with the new entry 5. What happens when the search key of an existing entry in the dictionary is changed?

Answer: could make that entry or other dictionary entries impossible to find.

6. Name three categories of linear implementations of a dictionary.

Answer: any three of … Sorted by search key array based, sorted by search key link based, unsorted array based, unsorted link based 7. What must a sorted linear array-based implementation of the ADT dictionary do during an addition and when removing an entry?

Answer: shift the data 8. The header file for a class of dictionary entries, called Entry, overloaded what two operators?

Answer: the equality operator == and the greater than operator > 9. When does use of the binary search tree implementation of the ADT dictionary become less efficient?

Answer: when the dictionary approaches a linear shape, comparable to a linear link-based implementation 10. Name two reasons for studying the linear implementations of an ADT dictionary?

Answer: any two of … perspective, efficiency, and motivation 11. A hash function maps an integer into a(n) _______________________.

Answer: array index 12. When is a perfect hash function possible?

Answer: when you know all the search keys 13. What are two requirements for a hash function?

Answer: easy and fast to compute, place entries evenly throughout the hash table.

.

Chapter 18 Questions 14. Use modulo arithmetic to determine the index for a key 1234 for a table of 101 entries.

Answer: 22 15. When using linear probing, what must be done when removing a dictionary item so that later hashing and linear probing still work correctly?

Answer: when the item is removed, specify the status of the table location as removed (previously occupied, now available) 16. What does primary clustering cause?

Answer: long probe searches and there a decrease in overall efficiency in the hashing process.

17. You have 650 table entries in a hash table with size of 1500. What is the load factor?

Answer: 0.4333 18. Name three major concerns which constitute a good hash function.

Answer: function easy and fast to compute, function scatters data evenly throughout hash table, how well does function scatter random data

.

Chapter 19 Questions Multiple Choice 1. If you use a binary search tree to implement an ADT dictionary, when does the efficiency of this implementation suffer? a. when the tree loses its balance b. when the tree is too balanced c. when the data portions of the nodes are too large d. when a node accidentally has three branches Answer: A 2. What is sensitive to the order of additions to and removals from a binary tree? a. the contents of the nodes b. the height of the tree c. the complexity of the links d. the implementation of the binary tree Answer: B 3. A binary tree is considered balanced if the heights of its two subtrees differ by a. at least 1 b. exactly 1 c. at most 1 d. zero Answer: C 4. You can traverse a 2-3 tree in sorted order by performing the analogue of a(n) _______ traversal on a binary tree. a. pre-order b. post-order c. tri-order d. in-order Answer: D 5. A 2-3 tree with n nodes cannot be taller than a. log2(n + 1) b. log2(n) c. n + 1 d. 2n + 1 Answer: A 6. A 2-3 tree implementation of a dictionary is of what efficiency for all its operations? a. O(log2(n + 1)) b. O(log n) c. O(n) d. O(n + 1) Answer: B 7. In a 2-3-4 tree, how many data items must a node have if it has 4 children? a. 2 b. 3 c. 4

.

Chapter 19 Questions d. 5 Answer: B 8. A red-black tree has the advantages of a 2-3-4 tree … a. but requires more storage b. and requires the same amount of storage c. but requires less storage d. but is less complicated Answer: C 9. What distinguishes the root of a red-black tree? a. it is red b. it is either red or black, but will have 4 children c. it is either red or black and has exactly 1 child d. it is black Answer: D 10. When working with a red-black tree, splitting nodes involves color pointer changes, called rotations. What does this do to the tree? a. shorten the tree b. lengthen the tree c. keeps it the same length d. reverses the tree Answer: A

.

Chapter 19 Questions True or False 1. The efficiency of using a binary search tree to implement an ADT dictionary suffers when the tree loses its balance.

Answer: True 2. Numerous additions to and removals from a binary search tree will invariably destroy its balance.

Answer: False 3. You can search an AVL tree almost as efficiently as a minimum height binary search tree.

Answer: True 4. An AVL tree implementation of a dictionary is of equal difficulty to other implementations.

Answer: False 5. It can be proven that the height of an AVL tree with n nodes will always be very close to the theoretical minimum of log2(n + 1).

Answer: True 6. A 2-3 is pretty much the same as a binary tree.

Answer: False 7. A 2-3 tree is never taller than a minimum-height binary tree.

Answer: True 8. The leaf of a 2-3 tree must contain exactly 2 data items.

Answer: False 9. Searching a 2-3 tree is efficient.

Answer: True 10. Searching a 2-3 tree is more efficient than searching a binary search tree.

Answer: False 11. According to the text, maintaining the shape of a 2-3 tree is relatively easy.

Answer: True 12. A 2-3-4 tree requires the same amount of storage as a 2-3 tree.

Answer: False 13. The algorithms for adding data to and removing data from a 2-3-4 tree require fewer steps than those for a 2-3 tree.

Answer: True 14. Every red node of a red-black tree has a black parent and a red child.

Answer: False 15. Every path from the root to a leaf in a red-black tree contains the same number of black nodes Answer: True

.

Chapter 19 Questions

.

Chapter 19 Questions Short Answer 1. What is an AVL tree (not what do the initials stand for)?

Answer: a balanced binary search tree.

2. What restores the balance of an AVL tree?

Answer: rotations 3. What two operations do not change the structure of an AVL tree and proceed just as they would for an unbalanced binary search tree?

Answer: retrieval and traversal 4. In what situation is a binary tree considered balanced?

Answer: if the heights of its two subtrees differ by a most 1 5. The node N of a subtree itself has two subtrees. The left subtree has height 4, the right subtree has height 6. What is the balance factor of node N? Answer: -2 (negative 2) 6. A 2-3 tree is a tree in which each internal node has either ______ or ______ children and all leaves are at the same level.

Answers: 2, 3 7. Specify the values of two possible data items that could be in the empty node of this 2-3 tree.

Answer: any two numbers between 110 and 160 8. What is the efficiency of searching a 2-3 tree?

Answer: O(log n)

.

Chapter 19 Questions 9. Specify the value of the data item that could be in the empty node of this 2-3-4 tree.

Answer: any number between 70 and 90 10. You are searching or traversing a red-black tree. You can use the binary search tree algorithm, but what do you do with the color pointers?

Answer: ignore them

.

Chapter 20 Questions Multiple Choice Questions 1.

A graph consists of ______ sets. a. two b. three c. four d. five Answer: a.

A subset of a graph’s vertices and edges is known as a ______. a. bar graph b. line graph c. subgraph d. circuit Answer: c.

2.

3.

Two vertices that are joined by an undirected edge are said to be ______ each other. a. related to b. bordering c. utilizing d. adjacent to Answer: d.

4.

A path is a sequence of ______ in a graph. a. vertices b. edges c. subgraphs d. cycles Answer: b.

5.

All ______ begin and end at the same vertex and do not pass through any other vertices more than once. a. paths b. simple paths c. cycles d. simple cycles Answer: d.

6.

Which of the following is true about a simple cycle? a. it can pass through a vertex more than once b. it cannot pass through a vertex more than once c. it begins at one vertex and ends at another d. it passes through only one vertex Answer: b.

7.

A graph is ______ if each pair of distinct vertices has a path between them. a. complete b. disconnected c. connected d. full Answer: c.

8.

A graph is ______ if it has at least one pair of vertices without a path between them. a. complete

.

Chapter 20 Questions b. disconnected c. connected d. full Answer: b.

9.

A complete graph has a(n) ______ between each pair of distinct vertices. a. edge b. path c. cycle d. circuit Answer: a.

10. A ______ can have duplicate edges between vertices. a. spanning tree b. connected graph c. complete graph d. multigraph Answer: d.

11. A self edge is also called a ______. a. cycle b. loop c. circuit d. multigraph Answer: b.

12. The ______ of a weighted graph have numeric labels. a. vertices b. edges c. paths d. cycles Answer: b.

13. The edges in a ______ indicate a direction. a. complete graph b. multigraph c. digraph d. spanning tree Answer: c.

14. If a graph has a directed edge from vertex x to vertex y, which of the following is true about x and y? a. y is a predecessor of x b. x is a successor of y c. x is adjacent to y d. y is adjacent to x Answer: d.

15. A graph-traversal algorithm stops when it ______. a. first encounters the designated destination vertex b. has visited all the vertices that it can reach c. has visited all the vertices d. has visited all the vertices and has returned to the origin vertex Answer: b.

16. A ______ is the subset of vertices visited during a traversal that begins at a given vertex. a. circuit

.

Chapter 20 Questions b. multigraph c. digraph d. connected component Answer: d.

17. An iterative DFS traversal algorithm uses a(n) ______. a. list b. array c. queue d. stack Answer: d.

18. A ______ order is a list of vertices in a directed graph without cycles such that vertex x precedes vertex y if the graph has a directed edge from x to y. a. graphical b. topological c. hierarchical d. spatial Answer: b.

19. A ______ is an undirected connected graph without cycles. a. tree b. multigraph c. digraph d. connected component Answer: a.

20. A connected undirected graph that has n vertices must have at least ______ edges. a. n b. n – 1 c. n / 2 d. n * 2 Answer: b.

21. A connected undirected graph that has n vertices and exactly n – 1 edges ______. a. cannot contain a cycle b. must contain at least one cycle c. can contain at most two cycles d. must contain at least two cycles Answer: a.

22. A connected undirected graph that has n vertices and more than n – 1 edges ______. a. cannot contain a cycle b. must contain at least one cycle c. can contain at most two cycles d. must contain at least two cycles Answer: b.

23. A tree with n nodes must contain ______ edges. a. n b. n – 1 c. n – 2 d. n / 2 Answer: b.

24. The sum of the weights of the edges in a path can be called all of the following EXCEPT ______.

.

Chapter 20 Questions a. length b. weight c. height d. cost Answer: c.

25. A ______ is a special cycle that passes through every vertex in a graph exactly once. a. multigraph b. tree c. spanning tree d. circuit Answer: d.

26. A(n) ______ begins at a vertex v, passes through every edge exactly once, and terminates at v. a. multigraph b. spanning tree c. Euler circuit d. Hamilton circuit Answer: c.

27. A(n) ______ begins at a vertex v, passes through every vertex exactly once, and terminates at v. a. multigraph b. spanning tree c. Euler circuit d. Hamilton circuit Answer: d.

28. An Euler circuit exists if and only if each vertex touches ______. a. two edges b. three edges c. an even number of edges d. an odd number of edges Answer: c.

29. Given the following graph and neighboring list, the breath first order starting from vertex A is

a) b) c) d)

A, B, C, D, E, F A, E, C, B, D, F A, B, C, E, F, D A, B, F, D, E, C

Answer: C

.

Chapter 20 Questions True/False Questions 1. Adjacent vertices are joined by an edge.

Answer: True.

2. A simple path may pass through the same vertex more than once.

Answer: False.

3. All paths begin and end at the same vertex.

Answer: False.

4. A simple cycle only passes through one vertex.

Answer: False.

5. All complete graphs are connected.

Answer: True.

6. A connected graph has an edge between every pair of vertices.

Answer: False.

7. A connected graph can have a pair of vertices without an edge between them.

Answer: True.

8. Each edge in a graph cannot begin and end at the same vertex.

Answer: True.

9. In a digraph, each pair of vertices may be joined by only one edge.

Answer: False.

10. The adjacency matrix for an undirected graph is symmetrical.

Answer: True.

11. A connected undirected graph that has n vertices and exactly n – 1 edges cannot contain a cycle.

Answer: True.

12. The adjacency matrix of a graph is always symmetric with respect to the diagonal line.

Answer: False.

.

Chapter 20 Questions Short Answer Questions 1. Define a path between two vertices.

Answer: A path between two vertices is a sequence of edges in a graph that begins at one vertex and ends at another vertex.

2. What is a simple path?

Answer: A simple path is a path in a graph that does not pass through a vertex more than once.

3. What is a cycle?

Answer: A cycle is a path that begins and ends at the same vertex.

4. What is a simple cycle?

Answer: A simple cycle is a cycle that does not pass through a vertex more than once.

5. What is a complete graph?

Answer: A complete graph is a graph that has an edge between every pair of distinct vertices.

6. What is a self edge?

Answer: A self edge is an edge that begins and ends at the same vertex.

7. What is a weighted graph?

Answer: A weighted graph is a graph whose edges are labeled with numeric values.

8. What are two differences between a directed graph and an undirected graph?

Answer: First, the edges in an undirected graph do not indicate a direction, while each edge in a directed graph has a direction. Second, each distinct pair of vertices in an undirected graph has only one edge between them, while a directed graph can have two edges between a pair of vertices, one in each direction.

9. What are the two most common implementations of a graph?

Answer: The adjacency matrix and the adjacency list.

10. How does the depth-first search (DFS) strategy of graph traversal differ from the breadth-first search (BFS) strategy?

Answer: The DFS traversal strategy proceeds along a path from a vertex as deeply into the graph as possible before backing up. The BFS traversal strategy visits every vertex adjacent to a vertex that it can before visiting any other vertex.

11. What is a spanning tree?

Answer: A spanning tree is a subgraph of a connected, undirected graph that contains all of the graph’s vertices and enough of its edges to form a tree.

12. What is a minimum spanning tree?

Answer: A minimum spanning tree is a graph’s spanning tree for which the sum of its edge weights is minimal among all spanning trees for the graph.

13. How is the cost of a spanning tree calculated?

Answer: The cost of a spanning tree is calculated by finding the sum of the costs of the edges in the spanning tree.

14. What is the shortest path between two vertices in a weighted graph?

Answer: The shortest path between two vertices in a weighted graph is the path that has the smallest sum of its edge weights.

15. What is a planar graph?

Answer: A planar graph is a graph that can be drawn in a plane in at least one way so that no two edges cross.

.

Chapter 21 Questions Multiple Choice 1. A file contains ______ that are organized into blocks. a. records b. locations c. names d. addresses Answer: A 2. The number of records in a block is a function of what? a. the programming language b. the size of the records in the file c. the brand of the computer d. implementation of the data structure Answer: B 3. A location which temporarily stores data is called a a. bucket b. bag c. buffer d. record Answer: C 4. When considering an algorithm’s efficiency when working with external data, what is the dominant factor? a. the brand of the computer b. the programming language c. the skill of the programmer d. the time required for block access Answer: D 5. Which of the following is the most appropriate for sorting external data? a. merge sort b. radix sort c. selection sort d. bubble sort Answer: A 6. Hashing implementation is not good for which of the following operations on external data? a. retrieval b. sorted traversal c. addition d. removal Answer: B 7. An external data collection can be organized as a balanced search tree. What are the pointers to the child pointers? a. search keys b. index values c. block numbers

.

Chapter 21 Questions d. hash numbers Answer: C 8. If searching an external data collection organized as a balanced search tree, what is actually organized as the external search tree? a. the data file b. the hash index c. the blocks d. the index file Answer: D 9. If a node N in a search tree is to have m children, how many key values must the node contain? a. m – 1 b. m + 1 c. 2m – 1 d. log2 (n - 1) Answer: A 10. What is a good motivation for having multiple index files for external data? a. to save external file space b. allows multiple data organizations c. splits up the data easier d. save internal data storage Answer: B

.

Chapter 21 Questions True or False 1. External storage exists after program execution.

Answer: True 2. Generally there is less external storage than internal memory.

Answer: False 3. Without direct access files, it would be impossible to support the data-management operations efficiently in an external environment.

Answer: True 4. A file of integer records will have less records per block than a file of student records.

Answer: False 5. According to the text, you can read and write a block of records, but you cannot read or write an individual record.

Answer: True 6. To need to operate on only a single record of the file, there is no need to access an entire block from the file.

Answer: False 7. Some programming languages have commands that make it appear that you are accessing one record at a time, not a whole block.

Answer: True 8. Even if records are stored in a sorted file, it is still not possible to use a binary search algorithm to retrieve a specified record.

Answer: False 9. An index to a data file is conceptually similar to an index to an array.

Answer: True 10. In general an index record is larger than a data record.

Answer: False 11. It is possible (and can be useful) to keep multiple index files on a single data file.

Answer: True 12. Use of an index file increases the number of required block accesses of the data file, especially for adds and removals.

Answer: False 13. When external hashing is used, you hash the index file instead of the data file.

Answer: True 14. It is not possible to organize an index file as an external 2-3 tree.

Answer: False

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Chapter 21 Questions 15. In an external environment, the advantage of keeping a search tree short far outweighs the disadvantage of performing extra work, such as comparisons, at each node.

Answer: True 16. Never access the search keys of the index records without accessing the data record.

Answer: False 17. If a traversal must display the entire data record (and not just the search key), the B-tree implementation is less attractive.

Answer: True

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Chapter 21 Questions Short Answer 1. What are the two general ways that files are accessed for processing?

Answer: direct access and sequential access 2. You wish to access a specific data entry in a file. Contrast the ways this must be done in sequential access and direct access.

Answer: In sequential access you must traverse every entry of the file until you come to the specific data entry desired, similar to traversing a linked list. In direct access you access the specified data directly, much like accessing a specific element of an array.

3. Suppose a sequential file is being updated with adds and removals. Remembering that multiple records are stored in blocks, what may require costly file accesses?

Answer: shifting records 4. If using an index file, why don’t you need to keep the data file in any particular order?

Answer: data records can be added in any convenient location, then the index file can tell the program where to find the data record.

5. Although you do not need to organize the data file, why must you organize the index file?

Answer: so you can search and update the data file rapidly 6. Enumerate the steps required for addition of a record when an index file uses external hashing as specified in the text.

Answer: a. Add the data record to the data file, b. keep track of the number of the block that contains the new data record = p c. Use the search key from the data record in the hash function, i =h(searchKey) d. Add index record <searchKey, p> into the index file at block i 7. What are the characteristics of a B-tree of degree m ?

Answer: a. All leaves are at the same level b. each node contains between m – 1 and [m/2] records c. each internal node has one more child than it has records (with exception of the root) 8. What are the steps for removal of a multiply indexed record where one of the index files is by name, the other is by social security number.

Answer: a. Search the name index for the specified name index record b. Remove the appropriate data record from the data file, noting the social security number in the data record c. Search the social security index file for that social security number and remove this index record

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