**7/27**Welcome to 681!**8/27**A minor clarification: the preferred interpretation of*collaboration on the homework*is not "Dick does problem 1 and Jane does problem 2," but rather "Dick and Jane do problem 1 and Dick and Jane do problem 2."**9/1**The course packet that we are using as text was printed, but unfortunately, it is the wrong version. Please do not buy this version. There will be announcements in class and on the web when the correct version is in the Cornell Store.**9/1**I have posted the first few chapters of the course text. Click here to access. More will be posted if necessary.**9/2**Remarks on your homework solutions:- Whenever you give an algorithm, always prove it correct. Super formal proofs are not necessary, a good convincing argument will do.
- Give an analysis of the complexity of your algorithm if that is the point of the question. Again, there is no need to be overly formal.
- Please keep your solutions
*short*and*to the point*. Brevity is the soul of good computer science!

**9/2**Surprise! We have a course newsgroup, cornell.class.cs681. You may use this for technical discussions, posting general questions about the homework, etc. The course staff will try to respond to questions in a timely manner, or if you know the answer, post it yourself. Please try to avoid giving away any hints on the homework though.**9/2**We are using the course management system CMS. Kelly has entered everyone who preregistered, but I'm sure there are several of you who are missing. Please log on to http://cms1.csuglab.cornell.edu/ and check whether you exist, and if not please send your full name and netid to Kelly so she can enter you.**9/2**The course packets are in at the Cornell Store.**9/14**Jeff would like to make the following requests regarding the homework.- Work in groups. This hw was borderline on being too much to have good turnaround, but if the 26 people who handed in single assignments pair up (or triple up), it shouldn't be a problem. Numbers wise, there were 18 people who did assignments in groups.
- Obviously staple.
- You are encouraged to type solutions.
- Make proofs exceedingly clear. I shouldn't have to figure out why or how leaps of logic are true, even if they are. Also, I prefer figures to words and I generally prefer words to pseudo-code (or at least in addition to pseudo-code to explain it).

**9/14**We will extend the window for the prelim due to Succoth. Please see the info page for the new schedule.**10/4**Your take-home prelim is available. Sign out the exam with Kelly Patwell in 5147 Upson. Return the completed exam to Kelly within 72 hours after signing it out, but no later than 4pm Friday, October 15. There are six questions, all equal weight. You may consult your class notes, class texts, and any handouts posted to the CS681 web page, but nothing else. No collaboration is allowed. Partial credit will be awarded where appropriate, so be explicit.**Good luck!****10/5****IMPORTANT.**There is a typo on the prelim. Please delete the word "acyclic" in question 2. My sincerest apologies.**10/8**I will post the prelim on the web on Tuesday, 10/12, 4pm. That way you will be able to download it from the web if you have not picked it up by then.**10/10**I have posted some hints for homework 4.**10/14**Due to the convergence of homework due dates and prelims of several CS grad courses around this weekend, the due date for HW4 has been extended to Wednesday, October 20.**10/21**I have posted a slightly revised and clarified version of HW5.**11/10**If you downloaded HW7 before 10:43am on 11/10, please download it again. I have made a slight change.**11/10**I will be out of town on 11/12. Eva Tardos will be the guest lecturer. The topic will be the fast Fourier transform (FFT).**11/19**I apologize for my absence Monday and Wednesday. I had to go to Maine to deal with a family emergency involving my parents. I am hoping we can find a time to make up the two missed classes, perhaps the first part of study week.**11/22**Please remember to fill out your online course evaluation for 681. It is open now to Dec. 6. http://www.engineering.cornell.edu/CourseEval**11/22**We will have two*optional*extra lectures on Monday Dec. 6 and Wednesday Dec. 8 at the usual time and place. The topic will be counting problems.**12/3**Your takehome final exam will be available on Monday, 12/6. The procedure is the same as with the prelim. Sign out the exam with Kelly Patwell in 5147 Upson. Return the completed exam to Kelly within 72 hours after signing it out, but no later than 4pm Thursday, December 16. You may consult your class notes, class texts, and any handouts posted to the CS681 web page, but nothing else. No collaboration is allowed. Partial credit will be awarded where appropriate, so please be explicit.**Good luck!****12/7**I will be out of town Thursday Dec 8 till Tuesday Dec 14. If you have any questions on the exam during that period, I can be reached on my cell (607) 592-2437 or at my parents' house (207) 873-0522.**12/19**Final grades are posted. That's all folks! Thanks to everyone for your participation in the class. Have a good holiday.