When I was a TA for 211, I put together review questions to help my students make sure they understand the material. Since they may be useful to other students, I have organized them by category. Enjoy, and feel free to ask me about them!
If your answer differs from mine: It may be that your answer is right too. And, although I haven't yet absolutely confirmed that I'm mortal (get back to me in eighty years), I occassionally err. So, if your answer isn't mine, ask me about it. I'll be happy to confirm whether you're correct and to tell you that my answer is better. (Or to correct myself; I really haven't checked my answers very well.)
If a question puzzles you: Don't hesitate to visit my office (4617 Wean Hall) or to e-mail me. I will be very happy to discuss these problems.
About the difficulty level: My questions tend to range in difficulty from the easiest you'll find in 15-211, to harder that anything you should expect on a quiz, to the downright challenging. All the questions are worthwhile. If you're comfortable with all the questions (except maybe the challenge problems), you'll be doing very well.
Challenge problems: Occassionally I stumble on questions that are slightly beyond the expected aptitude of 211 students but just too neat to skip. These are indicated by the heading of Challenge problem. You should not feel that you don't understand if you can't get the answer to one of these, but they're worth considering.
Sources: I've made up most of these questions and answers on my own. Some are questions from recitation notes that I skipped due to lack of time. I also draw from Cormen, Leiserson, and Rivest's Introduction to Algorithms. (I think this is what CMU uses in its undergraduate Algorithms course.) I may occassionally draw from Standish, but not too often, both because you can read the textbook as well as I and because few of Standish's questions and exercises seem to involve the higher-level thinking skills we expect. I've tried to credit the sources when known.