When I logged into edX after January 1st, I saw a different course main page than what I was used to. Prior to 2019, I had finished all of week 0, week 1, and week 1 continued. That means I finished problems sets 0 - 2. On the main page it tells me to start on week 3 of the 2019 course format. But when I looked at the week before it, (week 2 of the 2019 course) I saw some unfamiliar concepts like Binary Search, Merge Sort, and Algorithms Summary that haven't been covered in week 1 continued of the 2018 course, but have been covered in week 2. If I continue with week 3 of the 2019 course, wouldn't that make me miss out on all the things I mentioned above? Am I supposed to ignore the 2019 course and just continue with 2018? Am I just supposed to start over with the 2019 format instead? I'm confused...
You're right, there are some substantial changes for 2019. A lot of the first half of the course content has been compressed into less time and some has been removed. However, the latter half of the course has now been expanded and more material added.
To complete the course, you need to continue with the 2019 version. You already have credit for the work submitted and graded in 2018, as indicated on your grading web page.
Since you're still at an early point in the course, I'd recommend that you go back to week 2 in the new 2019 course where you will find new content. For the psets, the work that you've already completed should have carried over. Your completed material should appear on your grading page. Anything missing needs to be completed using the new 2019 material.
If I have read the mappings from 2018 to 2019, it looks like you have completed psets 0,1, and 2 for the new year, but probably want to back up and review the lectures and maybe other videos from those weeks. So, check your grades and review the class material until you're satisfied you've covered any new material or missing psets, and then start with pset3.
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