Assessment Tool

Lecture 15: Linear & Binary Search

Content Tested: Applications of Searching Techniques

Lecture Content:

Searching an array
Linear search
Binary search
Comparing algorithm performance

Goals:

Develop ability to apply principles and generalizations already learned to new problems and situations
Learn concepts and theories
Develop capacity to think for oneself

Assessment Technique: Application Cards

Purpose:

Instructors can find out how well students understand the processes of linear and binary search by brainstorming activities that apply these techniques.

Activity:

In today's lecture we saw the searching techniques called linear and binary search. In your groups (or as an individual) describe some answers to the following questions.

1. Describe situations where you have used or could use binary search to locate something.

2. Describe situations where you have used or could use linear search to locate something. Could you also use binary search for the situation? Why or why not?

Possible Solutions:

The instructor might want to give some example situations so students understand their task.

1. Possible Answers

Finding pizza company listings in the phone book (example used in lecture)

Finding a library book on a shelf (searching for the call number since books are arranged in sorted order by call number)

2. Possible Answers

Finding a house number on a street. Even though these numbers are in sorted order, binary search doesn't make sense since cars don't have the capability of jumping to a particular house. Rather, one would drive along the street until he/she found the house number for which they are looking.
Looking for a person in a group. People in a group do not stand or sit in sorted order which is a requirement for binary search.
Looking for a song title on a CD. Songs are not generally listed in sorted order based on title on the song listing.
Looking for a cereal in the cereal aisle in a grocery store. Binary search would not work since cereal is not generally located on the shelves in a particular sorted order.

Possible Uses of Activity:

Have students write applications individually and submit these to the instructor anonymously. The instructor reads the applications and the class discusses the searching techniques in these applications.
Each student writes an application for each sorting strategy and explains their applications to the rest of the class.
Break students into small groups (2-4 people) and have each group find several applications. Have each group explain their applications to the rest of the class.