1. Lecture 3
CSE 331
Sep 3, 2010

2. Remember: Stick with your group

3. More on Group Leader Scribe

4. All Sep blog post slots are gone!

5. Upcoming deadlines Sep 7: Form your group (email me the full names)
Sep 10: Teams can swap members

6. Don Knuth

7. Don Knuth Reward Checks

8. Questions/Comments?

9. What are Algorithms? A series of steps designed to solve a problem
A geometric way of solving problems
An abstract mathematical solution for a problem

10. Knuth’s Definition An algorithm is a finite, definitive, effective
procedure with some input and some
output

11. Why care about algorithms- II
Driving directions

12. Why care about algorithms- II
Computing Bestsellers on the fly

13. Why care about algorithms- II
Booking cheapest air tickets

14. Why care about algorithms- II
Google searches

15. Why care about algorithms- II
Data compression

16. Why care about algorithms- II
Error correction

17. (And I could) go on…

18. Read Chazelle’s article

19. Questions/Comments?

20. From problem to software

21. Main Steps in Algorithm Design
Problem Statement
Real world problem
Problem Definition
Precise mathematical def
Algorithm
“Implementation”
Data Structures
Analysis
Correctness/Run time

22. Worst-case analysis Correctness should hold for every valid input
Why worst-case?
Resource usage by the worst-possible input
What resources?

23. Hence, Brad Pitt is a goat.
The language of proofs
Brad Pitt had a beard
waleg.com
Every goat has a beard
animaldiversity.org
Hence, Brad Pitt is a goat.

24. Questions/Comments?

25. National Resident Matching

26. (Screen) Docs are coming to BUF
Buffalo General
Hawkeye (M*A*S*H)
Millard Filmore (Gates Circle)
JD (Scrubs)
Millard Filmore (Suburban)

27. What can go wrong?

28. The situation is unstable!

29. What happens in real life
Preferences
Information
Preferences

30. NRMP plays matchmaker

31. Stable Marriage Problem
David Gale
Lloyd Shapley