Lecture 20 - Announcements / Notes

Announcements

• No official labs this week.
  • TAs will be available in their labs for extra office hours
• Practice final exam problems to be released soon (by Wednesdy, I hope)

Plan for Today

• P19 help?

• P19 Extra Practice Problems:

  • #1 - find the index of a value in a list, or -1 if it’s not there

    def find(v, lst):
        """ 1. Return the index of the first occurrence of v in lst. 
        Return -1 if v is not in the list. Precondition: lst is a list. """

  • #4 - same as above, but:

    • the list is sorted
    • you must do it more efficiently: you aren’t allowed to look at all elements in the list, even if the one you’re looking for isn’t there.

    def binary_search(v, sorted_lst):
        """ Return the index of the first occurrence of v in lst.  Return
        -1 if v is not in the list. Precondition: lst is a list of things that
        can be compared with the < operator, and is in sorted order 
        (i.e. lst[i] <= lst[i+1] for all i in range(len(lst)-1) """

• P20 setup - design your own sorting algorithm!