]> Resorting Lists Application Cards Kate April 19, 2004 Application Cards

Instructors can find out how well students understand how to select a sorting algorithm for reordering a list that's already been sorted under a different criterion.

Read the following scenario and answer the two questions. Be certain to back up your decisions.

You have been given a file of all the undergraduates majoring in computer science at your university. This list contains each student's name and and GPA ans is sorted in alphabetical order by their names. Your task is to sort the students by their GPAs (note that if two students have the same GPA, they should then be sorted by their names).

  1. How would you sort this list?
  2. What if you were asked to do this for the entire undergraduate body of your university?

Student answers will vary greatly. There are two key points to focus on, though. The first is to see if students mention using a stable sort to resort the list. Secondly, do students discuss computational efficiency? This point is of particular value on question 2.

Read through the applications and sort or mark them as "Good," "Acceptable," "Marginal," or "Wrong." Read through the piles again to make sure that you have not accidently misclassified a response. You might also want to sort the responses by the type of sorting algorithm used.

Choose three or four of the best examples from the "Good" pile. Emphasize understandability, but try to have a diversity of example domains. Also consider a few acceptable and marginal responses that highlight points you wish to discuss.

If you use an application in class as a bad or poor example, change the application just enough to disguise the example from the original authors.

Have students write applications individually and submit these to the instructor anonymously. The instructor reads the applications and the class discusses the merits of these applications. The instructor might want to describe what the code would look like for some of the applications. Each student writes an application and explains their application to the rest of the class. Break students into small groups (2-4 people) and have each group find two or more applications. Have each group explain their applications to the rest of the class. Develop ability to apply principles and generalizations already learned Learn concepts and theories in the subject Develop capacity to think for oneself Develop ability to think creatively Develop ability to draw reasonable inferences from observations Sorting Real World Scenarios Stable Sorting Memory Efficiency LOW MEDIUM MEDIUM MEDIUM Lecture Next Day Summary Class Discussion Small Group Discussions Homework Difficult to Enable Algorithms Data structures Design ADTs