CSE116 / CSE504
Introduction to Computer Science II
Dr. Carl Alphonce
343 Davis Hall
alphonce@buffalo.edu
Office hours:
Thursday 12:00 PM – 2:00 PM
Friday 8:30 AM – 10:30 AM
OR request appointment via e-mail
PROFESSIONALISM
Turn off and put away electronics:
cell phones
pagers
laptops
tablets
etc.
© Dr. Carl Alphonce
ROADMAP
Last class
java.util.LinkedList exercise: remove
Today
asymptotic notation
Friday
exam Q&A session (bring questions!)
Exam #1
EXAM INFORMATION
Tuesday 3/8, 9:15 PM - 10:15 PM
Will cover material up to 2/26 (as well as WU3)
If you have a legitimate conflict (work/school):
get documentation, scan it as a PDF
e-mail it to me with subject line:
[CSE116] Exam 1 conflict documentation
NO LATER THAN 5:00 PM on 3/4 (FRIDAY)
WEDNESDAY 3/9 IS EXAM MAKE-UP DAY:
NO REGULAR LECTURE
© Dr. Carl Alphonce
Big Oh notation
Let g be a function that has non-negative
integer arguments and returns a non-negative
value for all arguments. A function f is said to
be O(g) if for some positive constant C and
some non-negative constant K,
f(n) <= C g(n), for all n > K
READ: CHAPTER 3 OF TEXTBOOK
Exercise
(see textbook, work out on your own)
What is performance of operations on data
structures we have seen so far?
operations:
add (find, insert, resize?)
contains (find)
remove (find, remove, resize?)
data structures
Bag
ArrayList
LinkedList / LRStruct
Stack
Queue
Worst-case behavior
We can measure behavior of an algorithm in the
best case (often not interesting)
average case (often most meaningful, but hard
to characterize and measure)
worst case (meaningful, easy to characterize
and measure)
MultiSet of size n
worst-case
insert
O(n)
contains
O(n)
remove
O(n)
ArrayList of size n
worst-case
insert
(at specific location)
(must search for location)
O(n)
O(n)
contains
O(n)
remove
(at specific location)
(must search for location)
O(n)
O(n)
LinkedList of size n
worst-case
insert
(at specific location)
(must search for location)
O(1)
O(n)
contains
O(n)
remove
(at specific location)
(must search for location)
O(1)
O(n)