CS 341: Algorithms Spring 2022



This course studies the major algorithmic design paradigms and mathematical tools for analyzing the running times of algorithms and detecting computational problems for which no efficient deterministic algorithm. Topics include: basics of analysis of algorithms; general algorithmic paradigms: (i) divide and conquer; (ii) greedy algorithms; (iii) dynamic programming; and (iv) graph algorithms; NP-completeness and its implications; and undecidability.

This is a hybrid course with online and in person components.

For the first 6 weeks (and possibly longer, TBD): In the remaining weeks: Applicable to the entire duration of the course: In the event that the university suspends in person activity:
Calendar description
Official course description from the course calendar
Handbook description
Longer course description from the Computer Science Undergraduate Handbook



Lecture materials (slides, videos when applicable) will be posted here. If you are happy to learn from the videos and/or slides, that's fine. When you need more details/examples, or if you like a text book format, here are the corresponding sections of the text, CLRS, together with our recommendations for alternative sources available online. For descriptions of the books, see Resources.

    Date Topics Slides YouTube CLRS Other readings
(* = highly recommended)
Week 1 L1 May 3 (ONLINE) Introduction PPTX,
PDF
(dark bg 1-up, 6-up)
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QA slides
Watch 1 * [Skienna] 1
L2 May 5 (ONLINE) Analyzing Algorithms PPTX,
PDF
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(light bg 1-up, 6-up)
QA slides
Watch 2.1, 2.2, 3 * [Skienna] 2
Week 2 L3 May 10 (ONLINE) Reductions PPTX,
PDF
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(light bg 1-up, 6-up)
QA slides
Watch 4.3, 4.4, 4.5 * for reductions: [Erickson] 1.1
L4 May 12 (ONLINE) Divide and Conquer I PPTX,
PDF
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(light bg 1-up, 6-up)
QA slides
Watch 4.1, 4.3, 4.4, 4.5; Optionally CLRS 2.3
Week 3 L5 May 17 (ONLINE) Divide and Conquer II PPTX,
PDF
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(light bg 1-up, 6-up)
Watch 4.2 [DPV] 2
L6 May 19 (ONLINE) Divide and Conquer III PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 9.3
Week 4 L7 May 24 (ONLINE) Greedy I PPTX,
PDF
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(light bg 1-up, 6-up)
Watch 16.1 [Erickson] 4
L8 May 26 (ONLINE) Greedy II PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 16.2
Week 5 L9 May 31 (ONLINE) Dynamic Programming I PPTX,
PDF
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(light bg 1-up, 6-up)
Watch intro of 15, 15.3; CLRS 15.1 Optional [Erickson] 3.1, 3.4
L10 June 2 (ONLINE) Dynamic Programming II PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch [DPV] 6.4
Week 6 L11 June 7 (ONLINE) Dynamic Programming III PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 15.4
L12 June 9 (ONLINE) Graphs I PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 22.1, 22.2 * [Erickson] 5.1 - 5.4
Week 7 L13 June 14 (ONLINE) Graphs II - DFS PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 22.3 * [Erickson] 5.5, 6.1
L14 June 16 (ONLINE) Graphs III - Topological sort, DAG testing, strongly connected components PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
Watch 22.4, 22.5 [DPV] 3.2
[Erickson] 6
Week 8 L15 June 21 (IN PERSON) Graphs IV - Minimum spanning trees PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
IN PERSON 23 [DPV] 5.1
[Erickson] 7.1, 7.2, 7.5
L16 June 23 (IN PERSON) Graphs V - Single source shortest path PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
IN PERSON 24.1, 24.3 [Erickson] 8.6
Week 9 L17 June 28 (IN PERSON) Graphs VI - All pairs shortest paths, formulating graph problems PPTX,
PDF
(dark bg 1-up, 6-up)
(light bg 1-up, 6-up)
IN PERSON 25.1, 25.2 [Erickson] 9*
No lecture June 30 [CANCELED] NO LECTURE
Week 10 L18 July 5 (ONLINE) Intractability I
L19 July 7 (ONLINE) Intractability II - complexity class NP
Week 11 L20 July 12 (ONLINE) Intractability III - Polynomial transformations
L21 July 14 (ONLINE) Intractability IV - NP completeness, satisfiability
Week 12 L22 July 19 (ONLINE) Intractability V - More NPC reductions, NP-hard, undecidable
L23 July 21 Tentative: [enrichment] parallel/concurrent algorithms
Week 13 No lecture (Friday schedule) July 26


Hand in a PDF file with your solutions via CrowdMark. We encourage you to prepare your solutions using LaTeX but you can use other software or submit handwritten assignments as long as they are legible. We have the right to take marks off for illegible answers.

When the CrowdMark instance is ready, all students enrolled in the class will receive an email with a link to their individual submission site. In order to submit, upload a separate PDF file (multiple pages are allowed) to each question. You may resubmit as often as necessary until the due date. (More detailed CrowdMark information is available at https://crowdmark.com/help/completing-and-submitting-an-assignment/.)

Marmoset will be used for the programming questions, and is available at https://marmoset.student.cs.uwaterloo.ca.

Assignments will appear in the following table, and will be due on the dates specified:

Assignment Number Date Posted Due (11:59pm EDT/EST) Hand In Via Markers Solutions
1 PDF, LaTeX Mon May 9 Thu May 19 CrowdMark Q1: Reza Bigdeli
Q2: Danny Kong
Q3: Yueheng Zhang
Q4: Cameron Seth
Learn
2 PDF, LaTeX Wed May 25 Thu Jun 9 CrowdMark Q1: Yueheng Zhang
Q2: Reza Bigdeli
Q3: Cameron Seth
Q4: Danny Kong
Learn
Programming 1 PDF
public input files ZIP
Wed Jun 1 Wed Jun 15 Marmoset
3 PDF, LaTeX Tue Jun 21 Thu Jul 7 CrowdMark

Instructions for Assignments: Your written solutions will be judged not only for correctness but also for the quality of your presentation and explanations. In questions that involve designing an algorithm, (i) describe the main idea first, (ii) present clearly written pseudocode (e.g., at a level of details mimicking the style of the lectures, the model solutions, or the textbook), (iii) give a correctness proof/argument if it is not immediately obvious, and (iv) include an analysis (usually, of the running time). In all assignments, unless otherwise directed, you are expected to justify any claims that you make. The level of explanation we generally expect is "enough to convince a skeptical TA". Usually this means that a complete formal proof from first principles is not needed (unless we say so). Furthermore, since this course is essentially all about efficient use of time and space, strive to make your solutions as efficient as possible. Solutions that are technically correct, but extremely wasteful in terms of time and space, will not receive full credit.

Collaboration Policy: The work you hand in must be your own. Unless specified otherwise, you can always use any result from the textbook, notes, or previous assignment just by citing it. You may discuss the assignment questions verbally with others, but you should come away from these discussions with no written or electronic records and you must acknowledge the discussion. Acknowledge any sources you have used. Any assistance received (from human or nonhuman sources) that is not given proper citation may be considered a violation of the university policies.

Late Policy: You will be allowed to hand in up to 2 written assignments 48-hours late without penalty. Lates may not be applied to programming assignments. Any subsequent late assignments will receive a grade of 0.

Since CrowdMark doesn't handle late days, the deadline posted needs to be set to the late deadline in order to allow late submissions to be graded. The number of lates used will thus have to be manually calculated. While we will periodically post our record of the number of lates that you have used, you are still responsible for keeping track of the lates you have used yourself. Anything handed in after the late deadline will not be accepted. The plan is to post solutions almost immediately after the late deadline on Learn.

We will not grant individual exceptions so that you can "keep" your two "free lates." The point of allowing two lates without penalty is to avoid this administrative work.

Programming Questions: There will be 2 programming assignments, where we ask you to code an algorithm. They may NOT be handed in late. However, this is not a software engineering course. We will not test your code against inputs that do not match our specifications. However, your program should take care of the edge cases that are crucial to the algorithm's correctness or analysis. For example, unless the problem states so, you should not usually assume that the input size is a power of 2. We will send out detailed instructions about how to submit programming questions.



We will use Piazza for all course announcements and as a forum for students to ask and answer questions. So you should enroll yourself at your earliest convenience. During Piazza discussions, please do not reveal the solutions to the assignments by requesting or offering detailed advice. We'll delete comments that reveal too much. Violations can result in academic sanctions.

Similarly, do not solicit hints or provide hints about how to solve the homework problems on other bulletin boards, such as Facebook. Violations can result in academic sanctions.

Piazza is not the place to dispute how assignments are marked. If you have a complaint, please follow the process given below.



Instructor Email (at school name dot ca) Office Hours
Trevor Brown t35brown TBA

Teaching assistant Email (at school name dot ca)
Aseem Baranwalarbaranw
Reza Bigdelirbigdeli
Danny Kongx32kong
Cameron Sethcjmpseth
Yueheng Zhangy3763zha

TA Office hours

Time (EDT/EST) Link
See Piazza See Piazza

Instructional support coordinator

Instructional support coordinator Email (at school name dot ca)
Sylvie Davies sldavies

Mark breakdown

Points of contact for common questions

Note: If you decide to e-mail the course staff, you must use your uwaterloo Quest e-mail account (WatIAM/Quest userID @uwaterloo.ca); otherwise we cannot verify who you are and are limited on what we can accept and respond to.

Help Topic Contact
Assignment, Missed Deadline: We do not accept emailed assignments or more than 2 late assignments. The last files submitted before the deadline will be marked (submit early and often, even if not finished).
If the deadline is missed due to illness or other valid, verifiable reason, see Missed Work Due To Illness below.
Assignment Marking Error: Re-mark request, due within one week of release of marks on CrowdMark/Marmoset. Contact the TA who marked the specific question and submit a written request. See TAs for contact information.
Assignment Recording Error: Grades will be made available through https://www.student.cs.uwaterloo.ca/~cs341/cgi-bin/displayMarks.cgi. If you notice an error in the recorded value, please contact Sylvie Davies (CS 341 ISC).
Course Website Error: Email CS341 course account
Handouts Error: Instructors - email or check consulting hours listed at Instructors
Enrollment: If Quest won't let you enroll or switch LEC or TUT sections without a permission/override number: Instructors and course staff are unable to help you—you must see a CS academic advisor.
General Course Help: TA office hours or instructor office hours.
Lecture Questions: TA office hours or instructor office hours.
Missed Work Due To Illness/Valid, Verifiable Reason (Assignments, Exams): Assignments, midterms, final exam: Validation required (see Verification of Illness Services at https://uwaterloo.ca/campus-wellness/health-services/student-medical-clinic but substitute Sylvie Davies (CS 341 ISC) for references to instructor. Make sure you also read the Math Faculty document on the consequences of submitting a VIF.
AccessAbility Services (AAS) exam accommodation forms (request to write at AAS): Submit to AAS at least 3 weeks before exam


If you are person who likes a more detailed text book format, here are our recommendations for sources available online.

Textbook: [CLRS] Cormen, Leiserson, Rivest, and Stein, Introduction to Algorithms (3rd ed.), MIT Press, 2009 (QA76.6 .C662 2009).

This book is available electronically through the UW library catalog.

Additional reference: [DPV], Dasgupta, Papadimitriou, Vazirani, Algorithms, available here.

Additional books:

The following resource is also useful for the course but more importantly for technical interviews you may have:



Plagiarism

Plagiarism is a very serious academic offence and is penalized accordingly. When you plagiarize you damage the learning experience for yourself and others. To avoid plagiarism accusations, do not copy other people's work, and cite all references that you use. If you work with others, only discuss general aspects of the course material, not specific solutions. Write up the solutions yourself, not in groups.

Mental Health Resources

Mental Health: If you or anyone you know experiences any academic stress, difficult life events, or feelings like anxiety or depression, we strongly encourage you to seek support.

On-campus Resources

Off-campus Resources

Diversity: It is our intent that students from all diverse backgrounds and perspectives be well served by this course, and that students' learning needs be addressed both in and out of class. We recognize the immense value of the diversity in identities, perspectives, and contributions that students bring, and the benefit it has on our educational environment. Your suggestions are encouraged and appreciated. Please let us know ways to improve the effectiveness of the course for you personally or for other students or student groups. In particular:

University Policies (University required text)

Academic integrity: In order to maintain a culture of academic integrity, members of the University of Waterloo community are expected to promote honesty, trust, fairness, respect and responsibility. [Check the Office of Academic Integrity for more information.]

Grievance: A student who believes that a decision affecting some aspect of their university life has been unfair or unreasonable may have grounds for initiating a grievance. Read Policy 70, Student Petitions and Grievances, Section 4. When in doubt, please be certain to contact the department’s administrative assistant who will provide further assistance.

Discipline: A student is expected to know what constitutes academic integrity to avoid committing an academic offence, and to take responsibility for their actions. [Check the Office of Academic Integrity for more information.] A student who is unsure whether an action constitutes an offence, or who needs help in learning how to avoid offences (e.g., plagiarism, cheating) or about “rules” for group work/collaboration should seek guidance from the course instructor, academic advisor, or the undergraduate associate dean. For information on categories of offences and types of penalties, students should refer to Policy 71, Student Discipline. For typical penalties, check Guidelines for the Assessment of Penalties.

Avoiding Academic Offenses: Most students are unaware of the line between acceptable and unacceptable academic behaviour, especially when discussing assignments with classmates and using the work of other students. For information on commonly misunderstood academic offenses and how to avoid them, students should refer to the Faculty of Mathematics Cheating and Student Academic Discipline Policy, https://uwaterloo.ca/math/current-undergraduates/regulations-and-procedures/cheating-and-student-academic-discipline-guidelines.

MOSS (Measure of Software Similarities) is used in this course as a means of comparing students' assignments to ensure academic integrity. We will report suspicious activity, and penalties for plagiarism/cheating are severe. Please read the available information about academic integrity very carefully.

Discipline cases involving any automated marking system such as Marmoset include, but are not limited to, printing or returning values in order to match expected test results rather than making an actual reasonable attempt to solve the problem as required in the assignment question specification.

Appeals: A decision made or penalty imposed under Policy 70, Student Petitions and Grievances (other than a petition) or Policy 71, Student Discipline may be appealed if there is a ground. A student who believes they have a ground for an appeal should refer to Policy 72, Student Appeals.

Note for students with disabilities: AccessAbility Services, located in Needles Hall, Room 1401, collaborates with all academic departments to arrange appropriate accommodations for students with disabilities without compromising the academic integrity of the curriculum. If you require academic accommodations to lessen the impact of your disability, please register with AccessAbility Services at the beginning of each academic term.