How can one comparison eliminate half a search?
In a sorted list, a comparison with the middle item can rule out an entire side. Binary search repeats that narrowing, gaining its efficiency from order that an unsorted collection does not provide.
Questions you could explore
- Why would one misplaced item undermine the reasoning?
- How can the search establish that an item is absent?
Start reading
- CS Unplugged, University of CanterburyThe Great Number Hunt: Sorted
CS Unplugged explains the sorted-search strategy through a number hunt; the key idea can be explored without running the classroom activity.
Ready to try your ideas aloud?
Your topic carries over. Record up to 2½ minutes, depending on your plan.