OSU eCampus CS325 Analysis of Algorithms review & recap

This post is part of an ongoing series recapping my experience in Oregon State University’s eCampus (online) post-baccalaureate Computer Science degree program. You can learn more about the program here.

Six-word summary: brutally difficult, but it’s over now!

CS325 – it me

In CS325 you’ll study recurrences, asymptotic bounds, probably every major sorting algorithm plus some silly ones, dynamic programming, graph traversal, recursion, linear programs, and more.

CS325 Review

Well, the rumors are true – this class is hard. I’d place it in a tie with CS162 for overall difficulty. But where CS162 tries to kill you with a brutal workload, CS325 tries to kills you with instructional materials that don’t adequately prepare you for the homework or the exams.

The lectures are not sufficient preparation for the homework – you’ll rely on YouTube and Stack Overflow to get through each homework question. The weekly homework assignments are time-consuming and the documents you prepare are long. Mine were anywhere from 5-15 pages of graphs, pseudocode, and written explanations for my work.

If you can take CS325 by itself, you should.

There was a noticeable (and distressing) disconnect between what was on the homework and what was on the exams. I scored 100% on the homework assignments, but failed the midterm. It’s like the homework and exams were from different classes!

A week or so after the midterm was graded it was opened up so students could see which questions they got wrong and dispute wrong answers, if they could prove they had it right. I thought for sure I’d prove the TAs wrong on at least one or two of mine, so I reworked all of my incorrect answers – and reworked and reworked them – until I eventually figured out what subtle thing I missed while taking the test.

I definitely struggled in this class, and for the first time I wondered if I even belonged in this CS program.

Class structure

  • 10 weeks
  • 7 assignments total
  • Group work: weekly graded discussions on Canvas, a 3-person group project the last two weeks of the quarter
  • Proctored midterm (20% of final grade), proctored final (20% of final grade)
  • No homework assignment the week leading into the midterm
  • No homework assignment once the group project at the end begins
  • You can bring a 8.5″ x 11″ sheet of typed notes (size 6 font!) into the midterm and the final with you

Tips for CS325

Take every extra credit opportunity (they’re rarer than you think). There was an extra credit opportunity on the first homework, but there wasn’t another opportunity until the last homework!

Comment early, often, and be helpful in the Canvas discussions. There’s an opportunity for 1 point of extra credit in each of these weekly discussions. I was able to earn it most weeks by doing all of the following:

  • As soon as the discussion thread was available, I “structured” the discussion by creating a series of replies, one for each homework question. In each reply, I posted the contents of the homework question for easy reference. This gave each homework question its own thread for my group mates to use.
  • When I figured something out on the homework, I posted pseudocode or a “how I approached this problem” guide to the Canvas discussion to help others. I spent easily 1-4 hours on creating this type of “tutorial”, every single week.
  • I started the homework right away. On Sunday I did the lectures, on Monday I did question 1, Tuesday I did question 2, etc. By midweek, I had half the homework done and was able to assist with answering questions from group members just starting theirs.

This was a ton of extra work. I see why people blew off the Canvas discussions. But the discussions did two key things for me:

  1. It helped my understanding of the various topics to revisit them and “teach” them to others
  2. The extra credit helped me squeak by with a 92.58% in this class, which got rounded up to a 93% (the cutoff for an A). I needed every. single. point. I could get.

Study recursion – put it on your exam sheet! A lot of the class’s materials (lectures, book reading, and homework) will “gloss over” recursive solutions to problems. They’ll be like, “this is the slow way to do it with recursion, now here’s the better way to do it with <the technique of the week>”.

You might be tricked into thinking the exam will want you to know the fancy technique – you’d be wrong. The midterm will expect you to produce the recursive solutions, which you won’t code for the homework or even look at past the few minutes they get in each lecture. I thought this was unfair of the class, so that’s my tip to future CS325 students: study the recursive solutions. Put them on your “cheat sheet”. Know them inside and out!

The extra credit competition among the final project groups is a poorly-designed zero-sum game that you have almost no chance of winning. Here’s how it works: 60+ groups implement algorithm(s) to solve a given problem in as little time as possible, then post their best running times to a Canvas thread. The assignment won’t tell you what “good” times look like – you’ll figure that out by looking at results that trickle in from the other groups. The winner is whichever group (or groups) has the best performance times in the two different categories.

I think this competition could be made better by awarding extra credit to any (and all) groups that can pass a certain benchmark, since that’s hard enough on its own. My group picked difficult-to-implement but highly performant algorithms and did our work in C++ and we still lost to multiple other groups by a little bit. Unless you’re super dying for that extra credit, I think the winning move here is not to play. Take the time you’d spend optimizing your final project towards an unknown goal and spend it studying for the final instead.

The book sucks. (This is the book.) Okay, maybe the book doesn’t suck, but it doesn’t map nicely to the class material and it won’t walk you through how to solve the kinds of problems you’ll face in the homework. I think the teacher requires this book just for the sake of requiring a book.

You’ll need the power of Google (and YouTube and Stack Overflow) to uncover how-to’s and guides for actually solving problems. I still did the readings every week, just in case something useful turned up, but the book is more like an introduction to the topic, not a guide. I relied almost 100% on external resources to actually learn this class’s material.

There are better videos and walk-throughs for every topic this class covers on YouTube and people’s blogs. Seek them out! There are people who recorded themselves going step by step through real problems pertaining to topics like recurrences and dynamic programming in ways the class-provided lecture videos do not. I owe my A in this class to the generous people of YouTube who took the time to demonstrate these difficult topics.

More than any other class before it, CS325 requires self-teaching and finding help on your own. Whether that experience is worth $1900 is left as an exercise to the reader – there is, of course, the argument that self-teaching is what you’ll do on the job so you might as well get used to it, but there’s also the argument that $1900 ought to buy you at least a little bit of hand-holding.

I’ll be in two classes next quarter: CS271 (Assembly and Architecture) and CS361 (Software Engineering I), so say hi if you’re in either of those with me!

OSU eCampus CS162 Intro to Computer Science II review & recap

This post is part of an ongoing series recapping my experience in Oregon State University’s eCampus (online) post-baccalaureate Computer Science degree program. You can learn more about the program here.

Six-word summary: Brutally paced pointers pointers pointers pointers

The beatings are over I survived CS162! If you were wondering where OSU’s eCampus computer science weeder course is, this is it.

The material is challenging and the workload is punishing. The video lectures are crap, but the book is good. The class isn’t well organized (expect poorly written assignments with unclear requirements). 10 weeks is nowhere near enough.

However: I learned a lot. I got faster than I ever thought possible and worked with topics I thought would have had their own standalone courses.

In this article: topics covered in CS162, survival guide, what I thought of the class.

Note: While I normally love to post code here, I can’t share any of my project code (against student code of conduct) or specific assignment requirements, test questions, etc.

Topics covered in CS162

The class is taught in C++ and teaches (or at least requires you to know):

  • pointers to arrays
  • pointers in arrays
  • pointers to pointers
  • pointers to instances of classes
  • passing pointers to functions
  • linked lists made of pointers
  • abstract class and subclasses
  • virtual functions
  • overloading operators (give == an exciting new meaning!)
  • polymorphism
  • writing functions that do something recursively, like reverse a string, sum numbers in an array, solve a math problem
  • data structures: queue, dequeue, stack, linked lists, circularly linked lists
  • sorting algorithms

    Equipment

CS162 is a programming class. Like CS161, I found my Macbook to be sufficient for this class.

I don’t know why they tell people to get a Windows PC and use Visual Studio. I didn’t need it and you won’t need it – there is no assignment based on Visual Studio knowledge.

In fact, judging just by Piazza posts, a number of students seemed confused by the extra files and the “another thing to learn” factor introduced by Visual Studio.

In case you are curious: I did every assignment in Sublime Text and a Terminal window.

Workload

At any given time expect to be working on a 1-week lab assignment and a 2-week project, and mid-course, a group project on top of the first two. You will also write a multi-page document (PDF) for each project with a test plan (input, expected outcome chart), your designs, ideas you changed along the way, reflections on the assignment. This document always took me at least 3-5 hours to complete to my standards. There’s a quiz every couple weeks (15 minutes, not proctored).

I’m a proactive student who started each week’s material the moment it was released, worked on it daily, and generally finished just moments before a new load of work was dumped onto me.

The first two weeks hit like a ton of bricks: a simple Langton’s Ant simulation by itself would have been a large assignment, but CS162 adds a user-navigable menu, input validation, user-adjustable parameters (dynamically sized board, variable turns to run, etc.), and other features that have to be designed, coded, tested, debugged.

Oh, yeah – it has a visual component, too.

There are also two lab assignments to complete while you work on the Langton’s Ant project.

This pattern continues until the end of the course. The toughest week was the one where I was working on a project, a lab, and a group assignment all at the same time.

CS162 Survival Tactics

It’s easy to find people complaining online about how disorganized and intense this class is but what I really wanted when I was in the thick of it was some help. (The OSU eCampus CS subreddit is a good place to look for advice on CS162, too.)

Here’s what I did (or wish I’d done sooner) that made CS162 more bearable.

Take it by itself (if you can)

I know there are financial aid reasons not to but if you’re normally taking 2 classes a quarter, consider taking CS162 alone (or at least with fewer classes than you normally would). It’s a ton of complex material – assuming you haven’t worked a lot with C++ pointers, memory, arrays, etc. yet – and the assignments are black holes for time.

Diagram things out on paper

I found many of CS162’s assignments too complex to hold entirely in my brain.

For example, here’s a crazy thing we did: create a circularly linked list (in C++), let the user fill it and delete nodes from it. When you exit the program, it has to unload from memory node by node. “Empty nodes” are marked with -1 for their values. This drawing I made helped a ton (actually, this was probably the 5th iteration of this drawing).

And here’s another one, this one showing how the heroes in the polymorphism project either rejoin the tournament queue or get kicked out to each player’s respective loser pile.

PS: Some people got really precious about their diagrams having to be works of art, but you don’t have to for these assignments. Just draw this stuff out, paper/pencil (or a little whiteboard) is sufficient, and plan to trash your first few drawings. If you need some material to bulk out your retrospective writing assignments for each project, photos of the diagrams you make are excellent fodder.

Go straight to Google (and Stack Overflow, and YouTube)

Sure, it sucks to pay $1880 to do so much self-teaching but you’ll get a lot of mileage out of the skill. The recorded lectures are crappy and I felt like they were wasting my time. There are better guides to all of the concepts covered in this class on YouTube.

Buy the book

Here’s the book on Amazon: Starting out with C++ Early Objects

I recommend getting a physical copy so you can have it open next to your computer while you work, and use your monitor(s) for your code and Stack Overflow. It’s the same book you use for CS161 (if you haven’t taken that yet, either), so at least you get two classes out of it. You can also buy the loose leaf edition to save some cash.

After two classes with it I can say it’s a good book. The examples are relevant to the coursework, they’re clear and easy to understand, and there are a good number of examples.

Start every week’s material the day it drops – and don’t count on weekends

Sometimes the new week will be released on a Friday. Sometimes a Saturday. Sometimes a Sunday! And no, the instructor doesn’t move that week’s deadline out just because you lost the weekend due to the materials not being released in a timely manner.

For this reason, I recommend setting up your life (at least for these 10 weeks) to allow for working on this class work during the week (ideally daily). Don’t expect to fit it all into the weekend. Even my light weeks were at least 15 hours spent on the class (usually closer to 25 or 30).

Check Piazza religiously

If they improve anything in CS162, I hope it’s the unclear assignment requirements. They requirements were notoriously bad – assignments are written in a conversational style and it’s hard to know what is really being asked for.

Many students took to Piazza (the class forum) to question (or worse, debate) the requirements until a TA or the instructor herself came along to clarify.

Pretty much every week went like this:

  1. New assignment comes out – oh no, it has unclear requirements
  2. Someone asks for clarification on Piazza
  3. TA makes a call and says do it X way
  4. 2 days later, another student asks the same question
  5. Different TA makes a different call on this new thread and says do it Y way
  6. They have a fight, triangle wins…
  7. You already coded it, so do you redo it to Y or keep it as X or what?

For what it’s worth, every time this happened (and I had already coded it), I kept my code the original way and still got 100% on the assignment.

Test on Flip!

So many things happened in my code in the Flip environment that did not happen on my Macbook. Weird things, too – things that weren’t easy to spot without thorough testing. I made the mistake of not testing on Flip until I thought I was done with the assignment, only to find heaps of bugs that only occurred in that environment.

Only after the class ended did I find out about this awesome way to use Git to deploy to Flip. (I was uploading in Filezilla like a n00b.)

Use Valgrind early and often

It’s a memory management tool that’s already installed on Flip and you won’t be able to find memory leaks without it. If you wait until you are done coding your assignment, it will be harder to find the memory leak. Upload your code and check it with Valgrind every so often and you will save yourself a lot of pain.

The worst weeks were weeks 1, 2, and the final project. 

Okay, they were all brutal. There were many weeks where I thought there was no way I would get everything done and I’m a workaholic. The biggest workloads were the first project (Langton’s Ant) and the final project at the end (make an adventure game).

You do actually have to contribute to the Canvas conversation topics

It’s a misguided requirement because these “conversation” threads quickly turn into 100+ people dumping commentary and links in one place. It’s not a conversation, it’s just a dogpile.

But if you contribute a few posts (I think I made 5 decent, paragraph-sized comments between January and March, evenly spaced throughout the quarter), it’s an easy 20 points that you will (probably) be very happy to have at the end.

Take every quiz twice

(Unless you get a great score the first time around, of course).

You get two attempts for each quiz. A quiz is 20 questions in 15 minutes. (I liked this format). Only the grade from the last attempt is kept. Questions are drawn from a larger pool, so you won’t get exactly the same ones the second time you take it.

My strategy was to use the first attempt to see what’s on the quiz and make my best guesses as to the answers. This gave me a feel for the questions and sometimes revealed tricky ones. I usually got about a 16/20 on my first try but Canvas tells you which ones you got wrong, and what the correct answers were, so this is a chance to see what you missed and study it some more. After a little studying I’d retake it, usually getting 18/20 or 19/20 that second time.

Grading

The final’s worth 15% of your grade, so save some steam for the end. There was a bonus, extra credit lab announced right at the last minute, too, but its points could only be applied to your lab grade.

  • Weekly labs – 30% of your grade
  • Quizzes – 15% of your grade
  • Projects – 30% of your grade
  • Group activities – 10% of your grade
  • Final project – 15% of your grade

Overall impression: OSU CS162

I hated it at times, but it was worth it. I never would have pushed through some of this stuff on my own, without a grade and a degree motivating me. OSU’s online CS is meant for people with a full-time job and the occasional signs of life outside of class but I had to take a couple days off work here and there to accommodate the workload, and I barely saw my family. The most difficult parts of this class – deciphering confusing and unclear requirements – were totally unnecessary. OSU should hire a proofreader and clean up CS162’s assignments. And some weeks the workload was just pure insanity – the week with the group project stands out in particular.

But… it’s over! And I got a 97%, so I’m going to take a much-deserved week to rest up for the next class.

Onwards to CS225!

Other student reviews of CS162

Leave a comment and I’ll update this post with your review!