The course staff must critically examine **close to ten thousand**
pages of homework submissions this semester! We desperately need your help
to make sure homeworks are graded and returned quickly. If you have any
questions or concerns about these policies, please don't hesitate to ask in
lecture, during office hours, or on Piazza.

- Homework Logistics: How to submit
- Form: How to write
- Content: What to write
- Absolutely no late homework.
- Don't plagiarize!
- Avoid Deadly Sins.

**All written homework solutions must be submitted electronically via Gradescope**. Please enroll yourself on Gradescope (entry code ERKJXG). Submit one PDF file for each numbered homework problem. Gradescope will not accept other file formats such as plain text, HTML, LaTeX source, or Microsoft Word (.doc or .docx).- You can register with Gradescope using any name and email address
you like. If you are using an alias or a non-university email address
on Gradescope, please
fill in this form to tell us who you are
so we can give you credit for your homework (there is no need to fill the form if you are using
your real name and university email address).
**If you are not logging into Gradescope with your real name or university email address, do not include your real name or your university email address in your homework solutions.** - Homework solutions may be submitted by
**groups of at most three students**. We*strongly*encourage (but will not require) every student to work in a group with at least one other student. Students are are responsible for forming their own homework groups. Groups may be different for each numbered homework problem.**For group solutions,**Even if the groups are identical, the submitter may be different for each numbered homework problem.**exactly one**member of each group submits the solution to each problem.- Whoever submits any group solution must also submit the names of the other group members via Gradescope. Gradescope will then automatically apply the grade for that submission to all group members. If this information is not entered correctly, the other group members' grades will be delayed or possibly lost entirely.
- If you discover that your name was omitted from a group
homework submission,
**please submit a regrade request.**

- As error correction, each submitted homework solution should
include the following information at the top
of the first page:
- Your GradeScope name
- Your Gradescope email address
- The problem number (of the form "X.Y")

*every*group member. If you are typesetting your solutions with LaTeX, please use our solution template (see pdf). **We will not accept late homework for any reason.**To offset this rather draconian policy, we allow some homework scores to be dropped; see the grading policy.-
We may
*forgive*coursework under extreme circumstances, such as documented illness, injury, or other emergency. We will compute your final course grade as if your forgiven work simply do not exist; your other work will have more weight. Please ask Timothy for approval and for the details.

Please make it easy for the graders to figure out what you mean in the short time they have to grade your solution. If your solutions are difficult to read or understand, you will lose points.

**Write**We*everything*in your own words, and properly cite*every*outside source you use.*strongly*encourge you to use*any*outside source at your disposal, provided you use your sources properly and give them proper credit. If you get an idea from an outside source, citing that source will not lower your grade. Failing to properly cite an outside source—thereby taking credit for ideas that are not your own—is**plagiarism**. The*only*sources that you are*not*required to cite are the official course materials (lectures, lecture notes, homework and exam solutions*from this semester*) and sources for prerequisite material (which we assume you already know by heart).**List everyone you worked with on each homework problem.**Again, we strongly encourage you to work together, but you must give everyone proper credit. If you work in a group of 20 students, then all 20 names should appear on your homework solution. If someone was particularly helpful, describe their contribution. Be generous; if you're not sure whether someone should be included in your list of collaborators, include them. For discussions in class, in section, or in office hours, where collecting names is impractical, it's okay to write something like "discussions in class".- Please see our academic integrity policy for more details.

**Write legibly.**If we can't read your solution, we can't give you credit for it. If you have sloppy handwriting, use LaTeX. Please don't submit your first draft. Writing legibly also helps you*think*more clearly.- We
*strongly*recommend typesetting your homework using LaTeX. (In particular, we recommend TeXShop for Mac OS X, TeX Live for Linux (already included in most distributions), and MiKTeX for Windows.) We provide a LaTeX template for homework solutions. - You are welcome to submit scans of hand-written homework solutions, but please write clearly using a black pen on plain white unlined paper, and please use a high-quality scanning app (or an actual high-quality scanner). We recommend printing your scanned document to check for readability before submitting.

- We
**Write sensibly.**You will lose points for poor spelling, grammar, punctuation, arithmetic, algebra, logic, and so on. This rule is*especially*important for students whose first language is not English. Writing sensibly also helps you*think*sensibly.**Write carefully.**We can only grade what you actually write, not what you mean. We will not attempt to read your mind. If your answer is ambiguous, the graders are explicitly isntructed to choose an interpretation that makes it wrong. Writing carefully also helps you*think*carefully.**Avoid Deadly Sins:****Write complete solutions, not just examples.**Don't describe algorithms by showing the first two or three iterations and then writing "and so on". Similarly, don't try to prove something by demonstrating it for a few small examples and then writing “do the same thing for all $n$”. Any solution that includes phrases like “and so on”, “etc.”, “do this for all $n$”, or “repeat this process”**may get a score of zero**. Those phrases indicate precisely where you should have used iteration, recursion, or induction but didn’t.**Declare all your variables.**Whenever you use a new variable or non-standard symbol for the first time, you must specify both its*type*and its*meaning*, in English. Similarly, when you describe any algorithm, you must first describe*in English*precisely what the algorithm is supposed to do (not just how it works). Any solution that contains undeclared variables**may get a score of zero**, unless it is otherwise*perfect*. This rule is especially important for dynamic programming problems.**Short**Unnecessarily long answers (which by definition are not perfect)*complete*answers are better than longer answers.**may get a score of zero**. See below.

**State your assumptions.**If a problem statement is ambiguous, explicitly state any additional assumptions that your solution requires. (Please also ask for clarification in class, in office hours, or on Piazza!) For example, if the performance of your algorithm depends on how the input is represented, tell us exactly what representation you require.**Don't submit code.**Describe your algorithms using clean, human-readable pseudocode. Your description should allow a bright student*in CS 225*to easily implement your algorithm in*their*favorite language.**Don't submit your first draft.**Revise, revise, revise. After you figure out the solution, then think about the right way to present it, and only*then*start writing what you plan to submit. Yes, even on exams; do your initial scratch work on the back of the page.

**Keep it short.**Every homework problem can be answered*completely*in at most two typeset pages (usually) or five handwritten pages; most problems require considerably less. Yes, I am aware of the crushing irony.**Omit irrelevant details.**Don't write "red-black tree" when you mean "balanced binary tree" or "dictionary". Don't submit code; we want to see your ideas, not syntactic sugar. If your solution requires more than two typeset pages, you are providing too many irrelevant details (usually).**Don't regurgitate.**Don't explain binary search; just write "binary search". Don't write the pseudocode for Dijkstra's algorithm; just write "Dijkstra's algorithm". If the solution appears on page 6 of Jeff's notes, just write "See page 6 of Jeff's notes." If your answer is similar to something we've seen in class, just say so and (carefully!) describe your changes. You will lose points for vomiting.**Automatic zero**: We will give an automatic zero to answers which we consider to be too long, unclear, and repetitious. We will also do it if we can not follow the logic of your answer. We might even do it without reading them. (Unlike some past semesters, we**do not**give any partial credit to "I don't know" answers.)

**Answer the right question.**No matter how clear and polished your solution is, it's worthless if it doesn't answer the question we asked. Make sure you understand the question before you start thinking about how to answer it. If something is unclear, ask for clarification! This is especially important on exams.**Justify your answers.**You must provide a brief justification for your solutions, as*evidence that you understand*why they are correct. Unless we explicitly say otherwise, we generally do*not*want a complete proof of correctness—because complete proofs would be too long, tedious, and unenlightening—but rather a high-level sketch of the major steps in the proof.**Proofs/justifications are only required on exams if we specifically ask for them.**- By default, if a homework or exam problem asks you to describe
an algorithm, you need to do several things to get full credit:
- If necessary,
**formally restate the problem**in terms of combinatorial objects such as sets, sequences, lists, graphs, or trees. In other words, tell us what the problem is*really*asking for. This is often the hardest part of designing an algorithm. **Give a concise pseudocode description of your algorithm.**Don't regurgitate, and don't turn in code!**Describe a***correct*algorithm.**Justify the correctness of your algorithm.**You usually won't have to do this on exams.**Analyze your algorithm's running time.**This may be as simple as saying "There are two nested loops from 1 to*n*, so the running time is O(*n*˛)." Or it may require setting up and solving a recurrence, in which case you'll also have to justify your solution.**Describe the fastest correct algorithm you can**, even if the problem does not include the words "fast" or "efficient". Faster algorithms are worth more points; brute force is usually not worth much. We will not always tell you what time bound to shoot for; that's part of what you're trying to learn.**However, if your algorithm is incorrect, you won't get any points, no matter how fast it is!**

- If necessary,