CS21 — Algorithmic Problem Solving

Announcements | Schedule | Grading | Study Sessions | Style | Integrity | Links
Introduction to Computer Science using Python


Welcome to CS21: Algorithmic problem solving! This course will introduce fundamental ideas in computer science while also teaching you how to write computer programs. We will study algorithms for solving problems and implement solutions in the Python programming language. Python is an interpreted language that is known for its ease of use. We also introduce object-oriented programming and data structures. A deeper coverage of these topics will be presented in CS 35.

This course is appropriate for all students who want to learn how to write computer programs and think like computer scientists. It is the usual first course for computer science majors and minors. Students with advanced placement credit or extensive programming experience should place out of this course and instead begin with CS 35.


Class info

Room: Science Center 240
Time: TR 1:15pm–2:30pm
Text: Python Programming: an Introduction to Computer Science by John Zelle

Instructional staff

Professor: Andrew Danner
Office: Science Center 253
Phone: (610) 328-8665
Office hours: MW 9:30-11:00a, F 1:30-2:30p, or by appointment

Student Services: Betsy Horner
Office: Science Center 255
Email: bhorner1
Phone: 957-6062

Student Mentors: Keith Blaha '10, Simone Fried '10, Carey Pietsch '10, and Mai Schwartz '10


1 Jan 23   Introduction
Writing and running programs in Python
Zelle Chapters 1-2
HW #1
Jan 25  
2 Jan 30 ASCII table Computing with numbers and strings
Using pseudocode
Zelle Chapters 3-4
HW #2
Feb 01 Quiz 1 (Solution)
Drop/Add ends (Feb 02)
3 Feb 06   Graphics
Using objects
Zelle Chapter 5
HW #3
Feb 08  
4 Feb 13   Functions
Zelle Chapter 6
HW #4
Feb 15 Quiz 2 (Solution)
5 Feb 20   Decision structures
Zelle Chapter 7
HW #5
Feb 22  
6 Feb 27   Loops
Zelle Chapter 8
HW #6
Mar 01 Quiz 3 (longer) (Solution)
7 Mar 06   Top-down design
Zelle Chapter 9
Mar 08    

Mar 13

Spring Vacation

Mar 15

8 Mar 20   Lists and Dictionaries
Zelle 11
HW #7
Mar 22 Quiz 4 (Solution)
9 Mar 27   Recursion
Zelle 13.1-13.3
HW #8
Mar 29 Last day to declare CR/NC or
Withdraw with a "W" (Mar 30)
10 Apr 03   Defining new classes
Zelle Chapter 10
HW #9
Apr 05 Quiz 5 (Solution)
11 Apr 10   Object-oriented design
Zelle Chapter 12
HW #10
Apr 12  
12 Apr 17   Linked lists HW #11
Apr 19 Quiz 6 (Solution)
13 Apr 24   Binary search trees HW #12
Apr 26  
14 May 01   Python applications HW #13
May 03 Quiz 7 (Solution)

May 18

Final exam 2pm-5pm. Room TBA


Grades will be weighted as follows:
40%Homework assignments
5%Class Participation
25%Final Exam

Homework policy

Programming assignments will typically be assigned in class at the beginning of the week and will be due before midnight the following Tuesday night. You are strongly encouraged to start early and to attend the study sessions for extra practice.

You will submit you assignments electronically using the handin21 program. You may submit your assignment multiple times, but each submission overwrites the previous one and only the final submission will be graded. Late assignments will not be accepted except in extreme situations and only if you contact me before the deadline. Even if you do not fully complete an assignment, you may submit what you have done to receive partial credit.

Study sessions

Several student mentors will assist me in class and run study sessions in the robot lab (Science Center 252) on Sunday and Wednesday evenings from 7-9pm. The student mentors are Keith Blaha '10, Simone Fried '10, Carey Pietsch '10, and Mai Schwartz '10. The course is also supported by Betsy Horner, whose office is Science Center 255 and can be reached by email at bhorner1 or by phone at 957-6062.

You are invited -- and encouraged -- to participate in these study sessions to prepare for quizzes, to discuss programming concepts, and to get friendly assistance in working on homework assignments. Our CS mentoring team is dedicated to helping students, who have no prior knowledge of computer science, learn to program in Python while keeping their senses of humor intact. As an added bonus, free food will be provided at the sessions.

Programming Style

Programming is not a dry mechanical process, but a form of art. Well written code has an aesthetic appeal while poor form can make other programmers and instructors cringe. Programming assignments will be graded based on style and correctness. Good programming practices usually include many of the following principles:

Academic Integrity

Academic honesty is required in all work you submit to be graded. You may not submit work done with (or by) someone else. You may not examine or use work done by others to complete your own work. You may discuss assignment specifications and requirements with others in the class to be sure you understand the problem. In addition, you are allowed to work with others to help learn the course material. However, with the exception of the student mentors, you may not work with others on your assignments in any capacity.

All code you submit must be your own with the following permissible exceptions: code distributed in class, code found in the course text book, and code worked on with an assigned partner. In these cases, you should always include detailed comments that indicates which parts of the assignment you received help on, and what your sources were.

"It is the opinion of the faculty that for an intentional first offense, failure in the course is normally appropriate. Suspension for a semester or deprivation of the degree in that year may also be appropriate when warranted by the seriousness of the offense." - Swarthmore College Bulletin (2006-2007), p. 53

Please see me if there are any questions about what is permissible.

Links that are related to the course may be posted here. If you have suggestions for links, let me know.

Basic Unix Commands
Python Documentation
Textbook site
How To Think Like a Computer Scientist: Learning with Python