Alright, Ostrovsky's lectures are getting better than what the reviews said, but I'd still read the textbook instead. The textbook explains everything in detail, and is pretty straight-forward except for the chapter with NP-Completeness.

Contrary to what other reviews say, I'd say the tip to doing well in this class is reading the textbook until you understand the material. (And proofs - you need to explain why your method is the most efficient). Solving more problems isn't necessarily the answer. I came in with no previous knowledge, just tried my best at understanding the material though the four HWs, and got an A. Please just don't copy the answers from online for the homework (you won't be prepared for the exam if you do!)

I personally feel like that the students who will do the best in this class would be Math majors who have experience with proofs. TAs are CS TAs so they don't fully expect full-math proofs. Just try to get your answer look like a Math-proof.

There are only 4 HW problems assigned per week but, it's gonna take quite some time. Many people suggest you to start early, but Ostrovsky often didn't cover the material until the day before the due date (at 8AM). I always ended up doing CS 180 homework at 2AM, though the TAs are pretty generous with grading the HW.

But to be honest, if you have a tight courseload, save yourself time by just reading the textbook and skipping the lecture. The only merit of going to his lecture is that Ostrovsky often hints what exam question will be on the exam (and might not be a freebie if you don't show up to class... Master's Theorem and Directed Acyclic Graphs for this year). I personally only showed up for lectures during Week 1 and Week 10, occasionally checking what the class is going over. Just ask a friend who's attending the lecture.

If you have a light courseload, I'd recommend you to read the textbook first, and just listen to Ostrovsky's lecture.

CS 180 really isn't a class where you can take good notes. It's more about understanding a concept and applying it. Proofs are the tools that help you understand why an algorithm works such way or why it's the most efficient.

And for Exams... It's really you see it or you don't.
You want to do some priming so you have a better chance of solving his problems. The exam questions however, aren't as difficult as the homework problems, and can be solved in given amount of time. (but your hand will hurt from writing a lot).

Read the example from textbooks as it helps you to understand the concept. Don't get too focused on proof of one example, since Ostrovsky's exams aren't about memorization. Try to learn how the process works. (Network-flow, Divide and Conquer, Dynamic programming)

He's a very kind professor though. Doesn't want many students stressed about his grades so his curve is always more lenient. I'd actually recommend taking CS180 with Ostrovsky if you are inclined to self-learn.

TL DR; Read the textbook (until you understand them). Kind professor with generous curve, but not the best lectures. Learn the concepts rather than memorizing examples.

This professor is really passionate about the subject which is great and wholesome but he isn't the best. I learned way more from discussion than from lecture. The homework is pretty hard but there are solutions online and if you do it you pretty much get full credit. The midterm was medium difficulty but I did super bad on it because I didn't read the book. Once I started reading the book everything changed and I started really understanding the material. He offered to drop the midterm and make the final worth more if it helps you and as a result my bad midterm grade was effectively erased and I got an A+! I cannot stress this enough, but the key to doing good in this class is reading the book and doing practice problems. Do problems on Geeks for Geeks, that website saved me. I cannot stress how much doing those practice problems prepared me for the final.

I think Ostrovsky is definitely getting better at teaching! This quarter he started writing out his lectures on the board instead of reading off of his slides (which is what I'm guessing he used to do based on previous reviews). This slowed down his pace a lot and made his lectures more interactive.
However, compared to other professors, he is still not the best lecturer. His handwriting on the board is almost illegible and a lot of the times he goes on tangents that are somewhat irrelevant to the class. He's really good at explaining things but it's really hard to survive this class without reading the book because the notes that he writes on the board aren't really "notes"...they're more like pictures/diagrams to help explain what he is saying. He rarely provides concrete definitions for mathematical terms/algorithms, and given the fact that this course is a very theory-intensive course, it's difficult to solely rely on his lectures to study.
For me, I just stopped taking notes after the 1st or 2nd week and tried my best to listen to what he was saying in class. I just read the chapters beforehand and his lectures made a lot more sense. Just read the book and you'll do fine.

My experience with this class was a little unconventional, as I was taking a very heavy courseload and had less time to dedicate to it early on in the quarter. Still, I found that this class wasn't that bad, and you could skip classes and just read the textbook without missing a beat.

Homeworks are annoyingly difficult at times, but doable if you form a study group. However, homeworks only compose 15% of the grade, with 40% being the midterm and 45% being the final, so your final grade will be determined pretty much from those two.

My main issue with this course was the hike in difficulty between the midterm and the final. The midterm was generally easy, with an average score of 60% and std. dev. of about 10%. The final, however, was unbelievably harder in comparison. I studied for two days straight before the final, and a minimum of 3 hours a day starting 10 days before the final, and I had no idea how to approach a majority of the problems. I assume there will be a much lower average and std. dev. on this final, and given the midterm reflected the material better I'd say it's better to study for the midterm more than the final honestly.

Anyways, the course isn't that bad, and Ostrovsky may be the most competent professor to teach the class of all professors who do. However, from my experience, I urge those taking it to treat the midterm like a final, as it could prove extremely difficult to set yourself apart from the rest of the class on the actual final, even if you study a ton.

Professor Ostrovsky is a great teacher! Though he can ramble off sometimes, I found that his passion for the subject really showed and it made me want to learn as well. Algorithms is a very interesting but difficult subject. He made it simple and easy to learn. And because he bases most of his lectures off of the textbook, you know exactly what to study. The midterm was really easy, requiring you to just think a little bit to apply the concepts you learned in class. All of the questions on the midterm/final were easier than the homework problems he assigned(about 4 a week). In general, great class as opposed to what other reviews on this site may say.

I learned nothing from his lectures. I have to self study by reading the textbook which thankfully is a saving grace at least for the midterm, but I just feel why would I take this class instead of just reading the textbook? His lecture slides have some errors, which for those who solely study the slides will not do so well unless they are smart enough or work hard enough to realize the mistakes.

Discussion sections do not really help at all. Most of the information I know is because I prepared leetcode problems over the summer, and because I am a junior, already am familiar with all types of problems. The grading for the exams seems to be arbitrary at best, where I either get full points or a big fat zero with obscure explanations as to why I lost those points. Asking for a regrade only yielded yet another obscure description without bumping my already abysmal exam scores.

The class itself depends way too heavily on the exams, which means if you are like me who perform somehow super badly on the exams, it is game over. By the way, I am in no way dumb, I am interning in the Big 4 this summer and know how to solve all these problems in the midterm and final, not to sound pretentious. I just lose almost all the points on the exam just because of obscure reasons even my friends do not know why, and I am just not a bright student academically.

Not the most exciting lecturer I've ever seen, but he's definitely a lot better than his reviews here suggest. I felt that he explained concepts pretty well, and he was pretty helpful when difficult concepts arose.

I think both Rafi and Mehka, (180 professors with really bad initial reviews) have gotten a lot better. I've only heard from friends talking about Mehka, but my experience with Rafi has been fairly positive

Course Breakdown was 15% HW, 40% Midterm, 45% Final. At tenth week, he opted to allow for the midterm to be dropped and the final to be weighted 85% depending on which benefited you more.

I enjoyed Ostrovskys lectures, but I'm aware I'm in the minority. I also know he can sometimes drone on for a long time on tangents. To me, however, he has a clear passion for the material and a silly nerdy sense of humor about it that is entertaining enough to get you through the worst of it. He'll also go fairly slow on concepts, so you can afford to space out in certain discussions.

In terms of difficulty, it's a bit nerve wracking to have two tests determine your grade. However, he does a good job not killing you with what he has on the exams. The algorithm design questions are similar in level to medium level leetcode questions and his proofs check for an overall understanding of the material rather than regurgitation. Studied a lot for the midterm and not as much for the final and did well on both. He will definitely curve you up if you need it.

At the end of the day, I think Ostrovsky is a good professor. Sometimes he can be dry as a lecturer, but follow the book and the TA's and you should be okay. My TA was Arman K who I would recommend since he cleared up a lot of little issues I had when learning. I would definitely take this course again.

At the first class, the professor look funny and he care about all students. He has no problem at all with regard to giving out PTEs. It turns out that you never need a PTE in that everybody drop the class or study by their own.

However, after a week, I was so so so disappointed. He is smart and intelligent and good in research. That's for sure. As a PhD student, I believe working with him to collaborate in a research must be a fantastic experience. But... the lecture (CS180), I'll probably say NO ... (soon).

It seems that he just use the slides from the publisher (how can you give a talk without preparing your own slide?). Somehow I disguise such a teaching style (reusing other's slides, especially when you use ALL of them and refuse to give it to students). YES! Everything you can find in TEXTBOOK. So why should I pay thousands of dollars to be here just for asking you to read TEXTBOOK out loudly?

I believe every instructor should put himself in student's shoes. I'm not here for listening your talk in a conference (if this is the case, he's okay despite of some accents). I "was" an instructor in a community college for several years before getting my PhD degree in UCLA, and I'm pretty confidence that his teaching style is very ineffective and irresponsible, at least, as a instructor in a "undergraduate" level class. Though, undoubtedly he is a great researcher and a wise, intelligent man. But in my opinion, no student would like such a teaching style.

I took CS 180 with Ostrovsky. In the beginning I thought he's a good professor; turned out later that he's not that good. He can explain topics pretty well, if you ask him; problem is that he doesn't seem to care enough to do so. In the beginning of the class this doesn't make much of a difference, but as the subject matter becomes more advanced and harder to comprehend, many students end up falling behind. In my class at least, he usually rushes through 50-70 slides from the book (which he refuses to share with students) in about 60-70 minutes, then lets everyone go as nobody "has any questions" for him. I was LUCKY to have a good TA to fill in the gaps to us during discussions. My advice: if you take that class with him, make sure to read the book material on your own, do _all_ homework assignments, and then look at homework solutions to ensure you got it right.