CS170: EFFICIENT ALGORITHMS & INTRACTABLE PROBLEMS

INSTRUCTORS: Christos Papadimitriou (christos AT cs) & Umesh Vazirani (vazirani AT cs)
LECTURES: MWF 3-4
PLACE: 2060 VALLEY LSB
OFFICE HOURS: Papadimitriou M Th 5-6 pm, 689 Soda. Vazirani M Th 1-2, 671 Soda.

TEACHING ASSISTANTS:
Alexandra Kolla (akolla AT eecs, 587 Soda, 642-3560)
Lorenzo Orecchia (orecchia AT eecs, 595 Soda, 643-4006)
Madhur Tulsiani (madhurt AT eecs, 595 Soda, 643-4006)

DISCUSSION SECTIONS(Final - starting from 10/1):
Wed 4-5: 310 Soda, Alexandra (10/11 in 405 Soda) Th 2-3: 215 Dwinelle, Alexandra.
Th 3-4: 87 Evans, Madhur.
Th 4-5: 75 Evans, Madhur.

TA OFFICE HOURS:
Alexandra: Tu 12-2pm, 551 Soda, starting 9/5
Lorenzo: Tu 11-12, 511 Soda (alcove)
Madhur: Th 10:30-12:30, 551 Soda

TEXTBOOK

The textbook for this course is "Algorithms" by Dasgupta, Papadimitriou & Vazirani. It will not be available at bookstores until about September 15. In the meantime, you can access the material online at Algorithms

COURSE CALENDAR

Topic Readings
1 August 28 Introduction and overview Chapter 0
2,3,4,5 August 30, September 1, 6, 8 Arithmetic, primality, RSA Chapter 1.1 - 1.4
6 September 11 Hashing Chapter 1.5
7,8&9 September 13, 15, 18 Divide-and-conquer Chapter 2.1-2.5
10&11 September 20, 22 Fast Fourier transform Chapter 2.5
12,13,14 September 25, 27, 29 Graph search Chapter 3
15 October 2 Shortest paths Chapter 4.1
15 October 4 Midterm 1  
16&17 October 6&9 Shortest paths (continued) Chapter 4
18, 19, 20, 21, 22 October 11, 13, 16, 18 , 20 Spanning trees and greedy algorithms Chapter 5
23, 24, 25 October 23, 25, 27 Dynamic programming Chapter 6
26, 27 October 30, November 1 Linear Programming Chapter 7
November 3 Midterm 2  
29, 30 November 6, 8 Linear Programming contd. Chapter 7
31, 32, 33, 34 November 15, 17, 20, 22 NP-completeness Chapter 8
35, 36, 37 November 27, 29, December 1 Coping with NP-completeness Chapter 9
38 &39 December 4 & 6 Quantum algorithms Chapter 10

RECENT ANNOUNCEMENTS

The grades for the course have been uploaded on bearfacts. The scores for the final are available here.
Have a good break!

A new list of grades has been uploaded here . It includes all homework/midterm grades. You have until Saturday 8AM to report any discrepancy with your records.

An updated list of grades has been uploaded here. Grades for HW12, 13, 14 and the "missing"
HW5's will be uploaded tonight. Please report any discrepancies (not regrade requests) by
Thursday (12/14) night.

Extra office hours before the exam
Final Exam Material Clarification regarding problem 10.3: The problem asks you to compute
Fourier transform "Modulo M". Please note that this is NOT like
problem 2.30 where we computed Fourier transform in a finite
field. For problem 10.3, you are supposed to compute the usual (using
complex roots of unity) Fourier transform. In this context "Mod M"
only means the basis states (of which the QFT is a superposition) are
|0>, |1>, ..., |M-1>.

The review session will be held on Monday (12/11) from 5:30 - 7:00 pm in 310, Soda Hall.

Problem 10.2 for HW14 is cancelled. For problem 10.3, refer to the first two paragraphs in section 10.3

The final exam is going to be held on Thursday, December 14, 12.30-3.30 pm, in 10 Evans. A review session will be held on Monday, time and location TBD.

Problem 8.13(e) for HW-13 has been made optional

Problems 9.2, 9.3 added to HW-13. An additional hint for problem 8.13 has also been added.

A list with all grades recorded so far has been uploaded to this page. The leftmost column contains the sudent's SID number, mod 164617.

HOMEWORKS

All homeworks are due Friday at 4:00pm unless otherwise stated. Turn in your homeworks in the box labeled "CS170" on the 2nd floor of Soda Hall. Please begin your answer to each problem on a new sheet of paper. Please ensure that each sheet is labeled with your name, SID number, section number, and "CS170--Fall 2006". You risk receiving no credit for any homework submitted without this information. Please take the time to write clear and concise solutions; we will not grade messy or unreadable submissions. The lowest two homework scores will be dropped. No late homeworks will be accepted.

EXAMS

There will be two midterms and one final. Dates and other details will be announced in due course.

QUIZZES

There will be a short quiz at the beginning of class on randomly selected dates. The quiz will consist of a small number of very simple questions related to the material of the previous class. The two lowest quiz scores will be dropped. The motivation for the quizzes is twofold: (1) to encourage you to review the material of each class before the next class; (2) to encourage on-time arrival at lectures.

ASSESSMENT

Your grade in the class will be determined as follows: Homeworks 25%; Midterms 20% each; Final 30%; Quizzes 5%.

COURSE POLICIES

Prerequisites: Formal prerequisites are CS61B and either CS70 or Math55. In particular, you should be comfortable with mathematical induction, big-O notation, basic data structures and binary heaps. If you need to refresh any of this background, you should refer to the relevant portions of the book. It is also assumed that you have experience with programming in a standard imperative language such as C, C++ or Java. Although most homeworks will be pencil-and-paper exercises, you may also be expected to do some small programming assignments.

Contact Information: The instructor and TAs will post announcements, clarifications, hints, etc. to this website and/or to the class newsgroup, ucb.class.cs170. Hence you must check this website and the newsgroup frequently throughout the semester. For information on how to access UCB newsgroups, go here (see also here for more).

If you have a question, your best option is to post a message to the newsgroup. The staff (instructor and TAs) will check the newsgroup regularly, and if you use the newsgroup, other students will be able to help you too. When using the newsgroup, please avoid off-topic discussions, and please do not post answers to homework questions before the homework is due.

If your question is personal or not of interest to other students, you may send email to cs170@cory.eecs. Email to this address is forwarded to the instructor and all TAs. We prefer that you use this address, rather than directly emailing the instructor and/or your TA. If you wish to talk with one of us individually, you are welcome to come to our office hours. If the office hours are not convenient, you may make an appointment with any of us by email. Please reserve email for the questions you can't get answered in office hours, in discussion sections, or through the newsgroup.

In a class this large, it can be challenging for the instructor to gauge how smoothly the class is going. We always welcome any feedback on what we could be doing better. If you would like to send anonymous comments or criticisms, please feel free to use an anonymous remailer like this one to avoid revealing your identity.

Collaboration: You are encouraged to work on homework problems in study groups of two to four people; however, you must write up the solutions on your own, and you must never read or copy the solutions of other students. Similarly, you may use books or online resources to help solve homework problems, but you must credit all such sources in your writeup and you must never copy material verbatim. Warning: Your attention is drawn to the Department's Policy on Academic Dishonesty. In particular, you should be aware that copying solutions, in whole or in part, from other students in the class or any other source without acknowledgment constitutes cheating. Any student found to be cheating risks automatically failing the class and being referred to the Office of Student Conduct.

Regrading Policies: Regrading of homeworks or exams will only be undertaken in cases where you believe there has been a genuine error or misunderstanding. Bear in mind that our primary aim in grading is consistency, so that all students are treated the same; for this reason, we will not adjust the score of one student on an issue of partial credit unless the score allocated clearly deviates from the grading policy we adopted for that problem. If you wish to request a regrading of a homework or exam, you must return it to your section TA with a written note on a separate piece of paper explaining the problem. The entire assignment may be regraded, so be sure to check the solutions to confirm that your overall score will go up after regrading. All such requests must be received within one week from the date on which the homework or exam was made available for return.

SOME HELPFUL HINTS

The following tips are offered based on our experience with Upper Division classes in CS Theory. If you follow these guidelines, you will make life much easier for yourself in this class.

1. Don't fall behind! In a conceptual class such as this, it is particularly important to maintain a steady effort throughout the semester, rather than hope to cram just before homework deadlines or exams. This is because it takes time and practice for the ideas to sink in. Make sure you allocate a sufficient number of hours every week to the class, including enough time for reading and understanding the material as well as for doing assignments. (As a rough guide, you should expect to do at least one hour of reading and two hours of problem solving for each hour of lecture.) Even though this class does not have any major projects, you should plan to spend as much time on it as on any of your other Upper Division technical classes.

2. Take the homeworks seriously! The homeworks are explicitly designed to help you to learn the material as you go along. Although the numerical weight of the homeworks is not huge, there is usually a strong correlation between homework scores and final grades in the class. Also, regardless of how well you did on the homework, read the sample solutions, even for the problems you got right. You may well learn a different way of looking at the problem, and you may also benefit from emulating the style of the solutions. (In science people learn a lot from emulating the approach of more experienced scientists.)

3. Make use of office hours! The instructor and TAs hold office hours expressly to help you. It is often surprising how many students do not take advantage of this service. You are free to attend as many office hours as you wish (you are not constrained just to use the office hours of your section TA). You will also likely get more out of an office hour if you have spent a little time in advance thinking about the questions you have, and formulating them precisely. (In fact, this process can often lead you to a solution yourself!)

4. Take part in discussion sections! Discussion sections are not auxiliary lectures. They are an opportunity for interactive learning, through guided group problem solving and other activities. The success of a discussion section depends largely on the willingness of students to participate actively in it. As with office hours, the better prepared you are for the discussion, the more you are likely to get out of it.

5. Form study groups! As stated above, you are encouraged to form small groups (two to four people) to work together on homeworks and on understanding the class material on a regular basis. In addition to being fun, this can save you a lot of time by generating ideas quickly and preventing you from getting hung up on some point or other. Of course, it is your responsibility to ensure that you contribute actively to the group; passive listening will likely not help you much. And recall the caveat above that you must write up your solutions on your own.