Algorithms are everywhere in CS — every program is an algorithm. Some algorithms warrant closer attention: those that are used and reused frequently, that are critical for an application's performance, or that solve important problems in CS in particularly elegant ways. These algorithms are often tightly coupled with particular data structures. This course examines algorithms and their data structures with an eye towards analyzing their efficiency and designing new algorithms in similarly efficient ways.
The fundamental goal of this course is to give you:
For an idea of the specific topics covered in the course, see the rough schedule for the semester.
When/Where: TR 9:25-10:40AM / CNS E210
Instructor: Mark Liffiton
Office: CNS C207B
Office Hours: MWF 11-12; TR 11-12; by appointment MW 2-3; or email/drop in any time.
Contact: Email is preferred (please start the subject with "CS255:").
For more pressing matters, my office # is 309-556-3535.
TA: Ed Thome
Office Hours: Mon 7-9; Wed 7-9; in CNS E210
Email: ethome @ iwu...
Semester schedule — tentative - see the Moodle for up-to-date details.
Online References — online textbooks, alternative sources, and general reference.
Moodle — assignments, quizzes, announcements, and other online resources will be here.
The "primary" textbook, whose organization I will be following and from which I will be drawing a decent amount of material is The Design & Analysis of Algorithms by Anany Levitin (details below); however it will not be strictly required for the course.
I've chosen this particular textbook because I like its organization and feel it has good, clear explanations. I will generally follow its sequence of topics, draw on it for lectures, and most likely use some exercises from it as well. However, the topics in this course are covered quite well in a wide range of resources, many available freely online. The particular book I've chosen is expensive, and so I want to make it clear that the same material can be found in many other books and websites. You will never absolutely need the chosen textbook, and I will make sure that any exercises I use from it are reproduced in the assignment.
Therefore, you can buy the primary textbook, or, with a bit of extra work, you can find relevant readings and explanations for anything we cover online. I will strongly encourage you to use these other resources whether you have the book or not. Owning the book, or another textbook, will give you an easy "one-stop" source, however.
It may be worthwhile to get together with other people in the course and buy or borrow two or three different textbooks to share. I've found study groups to be incredibly useful for this sort of material, and sharing textbooks is a natural extension of that. I will suggest two other books here, if you're interested in this approach.
The primary textbook I've chosen for the course:
| Title | Introduction to the Design and Analysis of Algorithms (2nd edition) |
|---|---|
| Author | Anany Levitin |
| ISBN | 0321358287 |
Another option, with good explanations and a lot of motivating real-world examples of algorithm design and analysis:
| Title | The Algorithm Design Manual |
|---|---|
| Author | Steve Skiena |
| ISBN | 1848000693 |
And finally, a very well-known, highly-respected, and quite dense book that is probably good for any computer scientist to have on his or her bookshelf:
| Title | Introduction to Algorithms (3rd edition) |
|---|---|
| Author | Cormen, Leiserson, Rivest, and Stein (the book is commonly referred to as "CLRS") |
| ISBN | 0262033844 |
We will primarily be using the Java programming language in this class. That said, the content of the course, the study of algorithms, is entirely language neutral. Algorithms themselves can be, and generally are, designed and analyzed in pseudocode, outside of the confines of any real programming language. Furthermore, any algorithm we study here can be implemented in any Turing Complete language.
Therefore, while the focus in class and for assignments will be Java, there is plenty of room for other languages as well. I am happy to help you, at any point, with code written in any language, whether it's a programming assignment or just something you wrote up to explore a concept. Some I know better than others, of course.
As a specific suggestion, I feel it would be beneficial for you to learn C in this class. The C language, along with its features such as explicit memory allocation/deallocation and directly-accessible pointers, is an important language to know for later courses (such as operating systems) and large segments of industry (such as operating systems... okay, and game programming). If you are interested in this possibility, come talk to me.
Overall, we can be flexible in this class, and I am open to your ideas on how we can make it as educational and enjoyable as possible.
The final grade will be based on the following breakdown:
| Assignments | 25% |
| Exam 1 | 20% |
| Exam 2 | 20% |
| Final Exam | 25% |
| Engagement | 10% |
Assignments will be posted on the course's Moodle site, usually about a week before they are due, and they will be collected there as well. Submissions should be in the form of plain text or PDF* for writing assignments, or .tar.gz archives for programming assignments. I will describe the expectations for submitting .tar.gz files in the assignment. I will aim to get them graded and returned to you by the following week.
Your lowest assignment score will be dropped.
Assignments will be due at set times; they will be considered late at any point after that time. An assignment will lose 10% of the total possible points for every day it is late, and after five days it will not be accepted.
Assignments can't be accepted at all after solutions have been handed out or the graded work has been returned to the class.
There will be two exams during the semester, and the second will primarily focus on the material seen since the first exam. The final will be cumulative, and it is currently scheduled for Wednesday, December 8, from 8:00-10:00am.
As you may have heard from other teachers: If everyone does well, that's great! I'm not going to lower anyone's grade to fit some predetermined grade distribution. However, scores given on individual quizzes or exams (especially exams) may not translate directly into a letter grade on the traditional scale. As explained quite well here:
"A percentage shows how much of a particular exam was dealt with successfully, but what test is so perfect that it could completely determine extent of knowledge or ability? If a student gets a grade of 90%, it does not mean they know 90% of everything in the subject. Wise students will begin to look at scores as a place on a continuum of achievement rather than analysis carved in stone."
If you would like to request a regrade, submit a request in writing (via email) within one week of receiving the graded assignment, exam, etc. Indicate exactly which part you believe deserves a different score and why.
Class time will be complementary to the reading, and you will need both in order to learn all of the material in this class. Furthermore, each student benefits from the engagement of all others in the class. Ten points of your final grade will be based on that engagement. Attending every class period on time and prepared will earn a base of 7 points; points can be gained by constructive participation, in class or out, such as asking questions, answering them, responding in the forum, sharing insights or useful/interesting resources with the class (posting in the forum, for example), investigating concepts beyond the requirement in class, working on small independent learning projects, and in many other ways; points can be lost for excessive (more than 3) unexcused absences, disrupting class (e.g., regularly showing up late), dominating the conversation, and the like.
Absences can be excused with documentation from health services or the Dean of Students' office, or if arrangements are made with me more than a week in advance. In general, if you know you will be missing a class, let me know as soon as you do.
I strongly encourage you to form study groups with your classmates, compare notes, explain concepts to one another, and generally help each other learn the material in this course.
Any material turned in for a grade must be your own individual work, though. You may work on concepts with other students, but I ask that you not discuss assigned problems until after the work has been turned in. This has two goals: 1) let the grades be a reflection of each student's own work, and 2) avoid situations where one person solves a problem and another records the answer as their own work without really learning. I understand that the line between discussing concepts and solving problems can be vague, so I ask that you use your own judgement with those two goals in mind and ask me if a situation is unclear.
Try to follow this rule of thumb: No matter what help you received figuring out the concepts involved, when you turn something in you should be able to reproduce the whole thing, working through the assignment again, without any outside help.
For details on the university's policies regarding academic honesty, please read the sections of the student handbook on conduct, cheating, and plagiarism here.
Use the web. The topics in this course are covered widely in a great variety of resources online. The Youtube video above is just one example, and such things are, in my opinion, very helpful learning tools. The online references page lists many others. Supplement our time in class and the book, if you have it, with resources on the web. I have provided links to some resources I think are valuable, but you should go out and find more as well. Search the whole web for a topic and see what comes up; use wikipedia (which will likely rate highly in the web search anyway) to get another view and to see links to related concepts; do a video search (or head straight to youtube) for visualizations or lectures; check out course websites for algorithms classes at other universities... Every single one of these will turn up something good. And when you find something that helps you, share it with the rest of us by posting in the forum on Moodle or sending me an email!