Overview

• Preliminaries.
  • Admin.
  • Questions.
• Four questions about insertion sort.
• Lab.

Preliminaries

Admin

• Writeup 6e and 8f. CSC 151.02 Writeup 28: Insertion Sort (Your Names)
• Note: The next time we have a fire alarm during a quiz, I'm not going to use the "everyone gets a ten" policy.
• Yes, I will teach you Anomia at some point if you'd like. Maybe during a Monday study break.
• Upcoming extra credit opportunities:
  • Tuesday, November 26, 4:15 p.m., JRC 209 a gaming event with the game [d0x3d!] Popcorn will be served.
  • Any self-care week activity during purgatory week.
  • One Grinnell rally on December 4 at 4pm.

Three questions about insertion sort

• What is the key idea in insertion sort?
  • Repeately insert an element into the correct place in an already sorted list
• How does insertion sort differ in lists and vectors?
  • In vectors, we have to shove things over to make room.
  • And we're mutating the vector

Let's think about this in English.

 vec: vector we're sorting
 boundary: end of the sorted region
 val: the val we're inserting
 pos: position we're shifting from

 Initialization: set pos to immediately left of the boundary
 If the value at pos is less than the value we're inserting, 
     Put value at pos+1
 Otherwise, 
     shift the value at pos right one spot
     Recurse at pos-1

• Why do we provide you with three different kinds of list-based insertion sort (and four kinds of insertion sort)?
  • One for numbers
  • One more general and one for keyed - different types
  • One for vectors

Lab