Quiz 06

Quiz 06



Important notes:
  1. Do not start until you are instructed to do so!
  2. You will have 15 minutes once the proctor says to start.
  3. You will have brief additional time after we stop to scan and submit your solutions.

  4. Just before the quiz...
    1. Have a fully-charged smartphone and laptop, and still plug both in if possible
    2. Log into Gradescope on your phone
    3. Change the screen timeout setting on your phone to never, so your screen doesn't go black if you don't interact with your screen for a while.
      • iPhones: Settings / Display & Brightness / Auto-Lock / Never
      • Android: Settings / Display / Screen timeout / 10 minutes (or the maximum amount of time)
    4. Turn on Do Not Disturb (or otherwise turn off all notifications).
    5. Position your webcam so we can see:
      • Your desk
      • The paper you are working on
      • Your writing utensil(s)
      • Both of your hands
      • Your phone

  5. During the quiz:
    1. You may not ask questions during the exam.
      • If you are unsure how to interpret a problem, take your best guess.
      • If you feel a question is unfair because you could not ask a question about it, please email the instructor after the quiz and describe your concern. (We are working hard to make the questions extra clear this year, but we want to know when we fail.)
    2. You may not touch your laptop or webcam.
      • This includes muting yourself at any point; the proctors may mute you though.
    3. All of these must be visible at all times:
      • Your desk
      • The paper you are working on
      • Your writing utensil(s)
      • Both of your hands
      • Your phone, with the quiz webpage
    4. For any tech fails (laptop or internet stops working, etc.):
      1. Stop taking the quiz
      2. Email the instructor (rileyrd@cmu.edu) right away
      3. We will reply soon to set up a 1-on-1 oral quiz with the course faculty

  6. After the quiz:
    1. Follow all proctor instructions on how to end the quiz.
    2. If you finish early, wait patiently until the end of the quiz. (Note: Don't use your phone...)
    3. Keep everything in view (as noted above) until the proctor calls "time".
    4. When instructed, use your phone to scan your quiz and submit the PDF to Gradescope.
    5. After submitting to Gradescope, hold your phone up to the webcam to show the receipt.
    6. Even then, remain in quiz mode until the proctor calls "all clear"

List Node Tracing [20 pts]

Consider the following code snippet that creates a linked list. You may assume that the ListNode class exists and was defined as in class.

ListNode<Integer> head = null;
ListNode<Integer> tmp = null;
ListNode<Integer> other = null;

head = new ListNode<Integer>(10);
// Stop and draw Diagram A.

head.next = new ListNode<Integer>(20);
// Stop and draw Diagram B.

tmp = new ListNode<Integer>(30);
tmp.next = head;
head = tmp;
// Stop and draw Diagram C.

other = head;
while(other.next != null) {
    other = other.next;
}
other.next = new ListNode<Integer>(40);
// Stop and draw Diagram D.

other = new ListNode<Integer>(50);
other.next = head.next;
head.next = other;
// Stop and draw Diagram E.

tmp = other.next.next.next;
other.next.next.next = null;
tmp.next = head;
head = tmp;
// Stop and draw Diagram F.

Draw the state of the linked list at each of the commented lines of code. The linked list is defined as starting at head.

The first one is drawn for you:

Draw the remaining five diagrams: Diagram B, Diagram C, Diagram D, Diagram E, and Diagram F.

Be sure to label each picture clearly with which Diagram it is.