1 / 10

Lecture 10

Lecture 10. CSE 331 Sep 21, 2012. HW 2 due today. Place Q2, Q3 and Q4 in separate piles. I will not accept HWs after 1:15pm. Other HW related stuff. HW 3 has been posted online: see blog/piazza. Solutions to HW 2 at the END of the lecture. Graded HW 1: pickup from TAs next week. EaGL-V.

finna
Télécharger la présentation

Lecture 10

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 10 CSE 331 Sep 21, 2012

  2. HW 2 due today Place Q2, Q3 and Q4 in separate piles I will not accept HWs after 1:15pm

  3. Other HW related stuff HW 3 has been posted online: see blog/piazza Solutions to HW 2 at the END of the lecture Graded HW 1: pickup from TAs next week

  4. EaGL-V http://www.cse.buffalo.edu/events/theory-V/

  5. 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

  6. Implementation Steps How to represent the input? How do we find a free woman w? How would w pick her best unproposed man m? How do we know who m is engaged to? How do we decide if m prefers w’ to w?

  7. Arrays and Linked Lists n numbers a1,a2,…,an Last Front a1 an 1 a3 a1 a2 a2 2 3 a3 Array Linked List O(1) O(i) Access ith element O(n) (O(log n) if sorted) O(n) Is e present? O(n) Insert an element O(1) given pointer n an Delete an element O(n) O(1) given pointer Static vs Dynamic Static Dynamic

  8. Today’s agenda O(n2) implementation of the Gale-Shapley algorithm More practice with run time analysis

  9. Gale-Shapley Algorithm At most n2 iterations 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 O(1) timeimplementation 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

  10. HW 2 due today Place Q2, Q3 and Q4 in separate piles I will not accept HWs after 1:15pm

More Related