1. Lecture 7
CSE 331
Sep 15, 2010

2. Reminder I will not accept HWs after 1:15pm HW 1 is due Friday
Prelim grading rubric up on the blog
I will not accept HWs after 1:15pm

3. HW 0 solutions posted
Use them as model solutions for your future HWs

4. Pre-emptive apology
icanhascheezburger.com

5. Return signed forms
I’ll need confirmation in writing. No graded material will be handed back till
I get this signed form from you!

6. Gale-Shapley Algorithm
Intially all men and women are free
While there exists a free woman who can propose
Let w be such a woman and m be the best man she has not proposed to
w proposes to m
If m is free
(m,w) get engaged
Else (m,w’) are engaged
If m prefers w’ to w
w remains free
Else
(m,w) get engaged and w’ is free
Output the engaged pairs as the final output

7. Preferences

8. GS algorithm: Firefly Edition1 2 3 4 5 6 1

9. Denise’s Q
Why not choose a free woman more smartly?

10. Today’s lecture At most n2 iterations of the while loop
GS algorithms always outputs a stable marriage