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CS 234Data Types and Structures

Units
0.50
Faculty
Mathematics
Subject
Computer Science

When it runs

  1. F24
  2. W25
  3. S25
  4. F25
  5. W26
  6. S26
  7. F26
  8. W27
  9. S27

Ran in 7 of the last 7 terms. Winter 2027: not on the schedule. Spring 2027: schedule not out yet.

Top-down design of data structures. Using representation-independent data types. Introduction to commonly used data types, including lists, sets, mappings, and trees. Selection of data representation.

Prerequisites

  • Complete 1 of the following
    • Must have completed at least 1 of the following:
      • CS116 - Introduction to Computer Science 2 (0.50)
      • CS136 - Elementary Algorithm Design and Data Abstraction (0.50)
      • CS138 - Introduction to Data Abstraction and Implementation (0.50)
      • CS146 - Elementary Algorithm Design and Data Abstraction (Advanced Level) (0.50)
    • Complete all of the following
      • Earned a minimum grade of 60% in each of the following:
        • CS114 - Principles of Computing for Science (0.50)
      • Must have completed at least 1 of the following:
        • CS115 - Introduction to Computer Science 1 (0.50)
        • CS135 - Designing Functional Programs (0.50)
        • CS145 - Designing Functional Programs (Advanced Level) (0.50)

Antirequisites

Leads to

Fall 2026 sections

Enrolment from UW Open Data, which can trail Quest by up to two days. Instructors and rooms: Schedule of Classes.
SectionClassEnrolledMeets
LEC 0015996320 / 360Online or by arrangement

Resources

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Reviewed on UW Flow

62% liked it69% easy68% useful

From 154 ratings and 45 comments on UW Flow. The most helpful comments, quoted as written, without names. Read them all on UW Flow.

  • Coming from cs136, very birdy. Course had 4 assignments and no final exam, only final assessment which we have week to do.
    For assignments, one half was written, was time consuming and irritating but doable, then the coding part was usually pretty easy, however the marking was abysmal.
    Most Assignment averages were in the 40s/50s. The tests were run in a way that if you get one test wrong, you get them all wrong. If you implemented a function even a bit different than they expected despite passing all tests, 50% deduction. I think there was an equal probability of getting a 100, 50, and 0 on the assignments.

    Dec 2022 · didn’t like it · 2 found this helpfulOn UW FlowRemove this

  • I guess it is ok - I would say CS 231 is much more useful as well as much easier than this. The writing part is about the same difficulty but the coding part is MUCH harder than CS 231. Yet overall it is manageable (it just requires many many many hours of testing and debugging... but the logic is not too hard for me who took CS 116). But if you were to have an elective for CS and you have an option between CS 231 and 234, take 231

    Dec 2022 · didn’t like it · 2 found this helpfulOn UW FlowRemove this

  • This is not a bird course(anymore) for students taking CS116.

    Nov 2022 · didn’t like it · 2 found this helpfulOn UW FlowRemove this

  • Super easy. If you have taken 136, even if you don't know python this class is a joke. Majority of assignments are implementing ADT's.

    Nov 2022 · liked it · 2 found this helpfulOn UW FlowRemove this

  • This is the worst course I have ever taken. The modules are like reading a book and offer little explanation of concepts. The assignments then ask you to code various different data structures, which is extremely difficult considering there are essentially no examples with code. Think about it this way: you read a math textbook with few examples that don't actually get solved using theorems, but instead using words telling you HOW YOU would do it; the assignment comes around and it asks you to solve questions 10x as difficult as the "examples" except this time use the theorems and some magical intuition that you should somehow have.
    Avoid this course at all costs.

    Nov 2022 · didn’t like it · 2 found this helpfulOn UW FlowRemove this

Discussed on r/uwaterloo

443 posts and comments in 312 threads mention CS 234, October 2012 to December 2024. Quoted word for word, newest first; each reply sits under the post and the comment that started its branch. Search r/uwaterloo for newer posts.

Fall 2024

any 2nd year cs courses that you can take with cs 116? 5 points, 6 comments

“Is there any 200 CS courses that are direct successors of 116? or do I need to take 136 no matter what?”

u/sour-sushi: “Cs230 cs231 cs234”

u/Efodoge: “Taking CS234 online right now along with Cs136, honestly a really good class for a less technical description and intuitive ways of developing of a lot of concepts and ADT’s compared to how they’re introduced in CS136 which is all technical jargon about memory for the most part. …”

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Course advice 2 points, 5 comments

“Very confused about 3A stat courses. Stat330 Stat331 Stat332 Stat333 Stat340 Stat341 How many stat courses a term is doable. Also i hated stat230 but loved stat231. …”

u/tried-n-tired: “… still a stat major bc the upper courses are so much better so don’t worry about that I took cs 234 which was pretty easy and bonus it’s online”

u/Crafty_Act1002: “Thanks!! Which 3 would u recommend together? Yeah i took cs234 already”

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Spring 2024

Online CS Courses? 2 points, 4 comments

“Does anyone have recommendations for CS courses that can be mostly done online? I'm talking about skipping 100% of all lectures and just attending midterms and finals. …”

u/LordHylian95: “CS 231 and CS 234 are both fully online and have final assessments instead of an exam”

u/Working_Ad4954: “Hi do yk of cs234 how hard is it?”

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Should I accept the offer 4 points, 9 comments

“I am in stat and CM major. I received an offer for an IT service intern today. And I interviewed for a Nissan coop today morning. …”

u/Working_Ad4954: “lol unrelated question but im thinking of declaring cm + stats. hows the employability through ww? and have u taken any of cs234, stat230, 230 yet? how were they? sorry i cant help your case ....”

u/Hot-Cartoonist-4295: “Cs234 is offering online and well organized, if you read the lecture notes and do the assignments, I think it’s easy 80s. Stat230 is depend on the prof, for me, I feel the content is not hard, but some prof may give very hard exams. …”

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Check it elsewhere for Fall 2026

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