1. Lecture 2
CSE 331
Sep 1, 2011

2. HW 0 due today I will not accept HWs after 1:15pm
Place Q1, Q2 and Q3 in separate piles
I will not accept HWs after 1:15pm

3. Office Hours Jesse: Wed 2-2:50pm; Th 1-1:50pm Swapnoneel: Tue 1-1:50pm
Bell
232
Swapnoneel: Tue 1-1:50pm
Atri: Mon, Fri 2-2:50pm

4. A clarification on scribing/blog post
Both have to be individual submissions

5. If you’re looking to form a group

6. Submit the form below
I’ll need confirmation in writing. No graded material will be handed back till
I get this signed form from you!

7. Sign up for blog posts/scribing

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

9. Questions/Comments?

10. National Resident Matching

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

12. What can go wrong?

13. The situation is unstable!

14. What happens in real life
Preferences
Information
Preferences

15. NRMP plays matchmaker

16. Stable Marriage Problem
David Gale
Lloyd Shapley

17. HW 0 due today I will not accept HWs after 1:15pm
Place Q1, Q2 and Q3 in separate piles
I will not accept HWs after 1:15pm

18. Questions/Comments?

19. Matching Employers & Applicants
Input: Set of employers (E)
Set of applicants (A)
Preferences
Output: An assignment of applicants to employers that is “stable”
For every a in A and e in E such that a is not assigned to e, either
(i) e prefers every accepted applicant to a; or
(ii) a prefers her employer to a

20. Simplicity is good

21. Matching Employers & Applicants
Input: Set of employers (E)
Set of applicants (A)
Preferences
Output: An assignment of applicants to employers that is “stable”
For every a in A and e in E such that a is not assigned to e, either
(i) e prefers every accepted applicant to a; or
(ii) a prefers her employer to a

22. Some Simplifying Assumptions
n employers and n applicants
Every employer has exactly one position open
Every applicant applies to every employer

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

24. Questions/Comments?