The CS 61 series is an introduction to computer science, with particular emphasis on software and on machines from a programmer's point of view.
- CS 61A concentrates on the idea of abstraction, allowing the programmer to think in terms appropriate to the problem rather than in low-level operations dictated by the computer hardware.
- CS 61B deals with the more advanced engineering aspects of software, such as constructing and analyzing large programs.
- CS 61C focuses on machines and how they execute programs.
In CS 61A, we are interested in teaching you about programming, not about how to use one particular programming language. We consider a series of techniques for controlling program complexity, such as functional programming, data abstraction, and object-oriented programming.
CS 61A primarily uses the Python 3 programming language. Python is a popular language in both industry and academia. It is also particularly well-suited to the task of exploring the topics taught in this course. It is an open-source language developed by a large volunteer community that prides itself on the diversity of its contributors. We will also dive deeper into interpreters, to which end we'll introduce the Scheme programming language as a way to explore functional programming, and Regular Expressions and the SQL programming language as a way to explore declarative programming.
Mastery of a particular programming language is a very useful side effect of CS 61A. However, our goal is not to dictate what language you use in your future endeavors. Instead, our hope is that once you have learned the concepts involved in programming, you will find that picking up a new programming language is but a few days' work.
A complete list of lecture topics, readings, and assignments appears in the daily schedule.
Math 1A is listed as a corequisite for CS 61A. That is, it may be taken concurrently. Math 10A or Math 16A are also fine. It is possible to take CS 61A without knowing or learning calculus—knowledge of calculus concepts will never be required to complete any of our assignments. However, taking calculus is a great way to brush up on the arithmetic and algebra that appear regularly in CS 61A.
Though there are no enforced programming-related prerequisites for CS 61A, we strongly recommend prior Computer Science coursework or other exposure to programming equivalent to CS 10 or a score of 3 or above on the AP Computer Science A exam. Some students take the course without any prior programming experience, but they typically must work substantially harder to master the material. If you have limited prior experience and you find it challenging to complete all of the required coursework in the first week, strongly consider taking another course first. You'll likely have a better experience taking 61A later, and you won't fall behind in any meaningful way by taking a preparatory class first. When surveyed, most students mentioned that they found CS 10 very useful in preparing them for 61A.
To build programming experience before taking CS 61A, we recommend that you first take a class that introduces you to programming. The most appropriate class within the Berkeley CS department is CS 10, described below, but you may also find similar classes at Berkeley extension or in online courses. Feel free to contact course staff if you are not sure what's best.
CS 10: The Beauty and Joy of Computing is an introductory computer science course which is similar to CS 61A but moves at a friendlier pace. CS 10 covers variables, functions, recursion, algorithmic complexity, object-oriented programming, and many other relevant CS 61A topics, with the overall content overlap being about 50%. CS 10 starts the semester in Snap!, a block-based programming language which allows students to focus on conceptual understanding without worrying about unfamiliar syntax. After the midterm, the course transitions into Python (the primary language 61A uses), applying the same concepts you already learned to the new language, as well as introducing new concepts more relevant to Python. CS 10 also covers big ideas and social implications that go beyond programming, showing you the beauty and joy of computing.
Data 8: The Foundations of Data Science is an introduction to data science designed to be accessible and useful for all Berkeley students. This course was built for students without prior programming experience. It teaches students to program in Python 3, but covers a much smaller subset of the language than CS 61A. Most of the course focuses on data processing and statistical techniques that are central to using computers to answer questions about the world. Taking Data 8 before 61A is a good way to gain prior programming experience, but taking CS 10 is a better way.
Rather than taking 61A, many students take one of these alternate Berkeley courses. It is possible to take 61A after taking one of these courses, but there is so much overlap in content that few students take 61A as well.
CS 88 (Not offered over the summer)
CS 88: Computational Structures in Data Science is an introduction to programming and computing that has more than 50% concept overlap with CS 61A. It is designed for students interested in data science who want to expand their knowledge of programming and program structures beyond what is covered in Data 8. Students who complete CS 88 can either proceed directly to CS 61B or subsequently take CS 61A, a path that offers a substantial amount of review because of the high topic overlap between the courses.
The course includes many events and opportunities for learning: lecture, lab, discussion, office hours, and more. Everyone learns differently, so not all of these events are required. However, it is recommended that you try everything out to figure out what combination of these events works best for you.
There are four 80-minute lectures per week in Dwinelle 155. Slides will be posted before each lecture. A recording of the lecture will be posted soon after each lecture occurs. This course moves fast, and lecture is tightly coordinated with section. Please attend or watch each lecture the day it is given and before you attend section.
There are four sections each week: two labs and two discussions. These sections are run by an amazing group of teaching assistants who have been carefully selected for their ability, enthusiasm, and dedication to learning. Getting to know your TA is an excellent way to succeed in this course.
In office hours, you can ask questions about the material, receive guidance on assignments, and work with peers and course staff in a small group setting. See the office hour schedule and come by in person or book an appointment online on the OH Queue. Appointments for each week will be opened on Sunday afternoons, but we don't anticipate appointments to run out. If they do, you're still welcome to swing by in person, as well as post on Piazza.
Our head TAs will also offer advising office hours, which are designed to help you navigate CS at Berkeley, Berkeley overall, and really anything that we're able to advise you on. You can book those appointments using any of these TAs' links from the blurb on the OH page.
Each week, there will be problems assigned for you to work on, most of which will involve writing and analyzing programs. These assignments come in three categories: lab exercises, homework assignments, and projects.
Lab exercises are designed to introduce a new topic. You can complete and submit these during the scheduled lab sections or any time before the deadline. Most students find that attending lab and collaborating with other students there is much more useful than working on lab assignments independently. We strongly encourage you to attend and collaborate on labs. Additionally, attendance at lab sections will count towards a participation score in your final grade.
Lab exercises are scored on correct completion. To receive credit, you must complete all of the problems that are not marked as optional and pass all tests. There is no partial credit on labs.
Weekly homework assignments let you apply the concepts learned in lecture and section to more challenging problems. Homeworks will typically be released on Mondays and due the upcoming Thursday.
Homework is scored out of 2 points, and every incorrect question costs you 1 point.
Homework Recovery Policy
You can recover one question per homework by attending a homework recovery session. Logistics will be released after the first homework assignment is due.
Recovery sessions describe how to approach and solve a past homework problem. You are welcome to attend these even if you don't need the recovery point.
Projects are larger assignments intended to combine ideas from the course in interesting ways.
For all projects except the first project (Hog), you are allowed and encouraged to pair program with a partner. Make sure to alternate roles so that both of you understand the complete results. We recommend finding a partner in your section, but course staff will also help with partner matching at various points in the semester. It is your responsibility to contact and collaborate with your partner. You may also work alone on all projects, although partners are recommended.
Projects are graded on correctness, with points earned for each problem successfully completed.
There will be two exams:
- The midterm exam will be held 6pm-9pm on Thursday, 7/14.
- The final exam will be held 6pm-9pm on Thursday, 8/11.
Exams will be taken on paper on campus in designated exam rooms. In the event that in-person exams are not allowed due to campus closure or room occupancy restriction, exams will be delivered remotely.
Unlike some courses, the particular subject matter of CS 61A makes it very difficult to ensure a fair exam in which many students are taking the exam in person and many others are taking it remotely. Since it is not likely that all on-campus students will have a suitable space to take a remote exam simultaneously, an in-person exam is the best available option, and this is why the default exam format is in-person.
Accommodations (DSP and Otherwise)
We will provide appropriate accommodations to all students enrolled in Berkeley's Disabled Students Program (DSP). To ensure that you receive the appropriate accommodations, have your DSP specialist send us a letter confirming your status and accommodations. We also aim to provide fair and appropriate accommodations to any students who, because of extenuating circumstances, may need them. For information on how to request accommodations, please see the "Accommodations Appointments" section below.
Remote section accommodations
In light of the ongoing Coronavirus pandemic, we understand that attending sections and exams in-person may be challenging for some students. To this end, we will be providing remote accommodations for all required sections:
- Lectures will be recorded and posted to the course website, so that students may watch asynchronously
- Synchronous attendance at lab and discussion sections will be required (with a number of excused absences allowed), but we will offer at least one fully remote lab/discussion pair, which will be marked on the sections site.
- You will be allowed to request a remote exam or other exam accommodations under specific circumstances. Details on how to request these for each exam will be released around one week prior to each exam.
Our hope is that these accommodations will make the course as accessible as possible for as many students as possible, but the default mode of instruction for the course is in-person. All students will be assumed to be taking the exam in-person unless remote accommodations are explicitly requested, and we cannot at this time guarantee remote support for resources such as office hours and small-group tutoring. We also will not be providing explicit accommodations for students not based in the Pacific timezone.
It will be technically possible to take the course fully remotely, but if you are unable to come to Berkeley to take the course this summer it is our recommendation that you take the course in the Fall instead.
If you need to request an extension, regardless of your DSP status, fill out this form. Submissions to this form will be visible only to the course instructors, and any TA marked with a "DSP" on the staff page.
Any extension request up to 24 hours will be approved automatically, so long as it is made in good faith. Any extension request up to 3 days made by a student with a DSP accommodation for assignment extensions will be approved automatically. All other extensions will be handled on a case-by-case basis.
There will never be a penalty for requesting an extension—we understand that life happens, and we want to ensure that all students are provided with the support and flexibility they need to succeed, regardless of personal circumstances.
If you're not enrolled in DSP, or are in the process of being onboarded by DSP, you may still be eligible for accommodations. You may also be eligible for accommodations if serious extenuating circumstances should come up during the semester.
If you believe you may require accommodations, please visit this calendar to book a short (20-minute) appointment with one of our student support TAs. You can also reach us at any time to discuss accommodations by emailing firstname.lastname@example.org.
All DSP and accommodations-related materials for this course are kept in a repository separate from the rest of the course materials, that is visible only to the instructors, selected staff, and course managers. Course managers are members of department staff, unlike course staff, that help manage situations such as DSP accommodations.
For any DSP and accommodations-related communications, please reach out to email@example.com, which will put you in touch with our student support team. This inbox is only visible to staff members marked with "cs61a@" on the TA and tutor pages. This inbox will be visible to future members of course staff, so if you ever have a communication that you wish to remain private, let us know and we can delete the email exchange once the conversation is resolved.
If you believe your accommodations may affect the TA who is teaching your section, and would like to inform that TA, you may wish to email us, and we can inform your section TA on your behalf. You are also welcome to reach out to your section TA directly.
The online textbook for the course is Composing Programs, which was created specifically for this course, based on the classic textbook Structure and Interpretation of Computer Programs. Readings for each lecture appear in the course schedule. We recommend that you complete the readings before attending lecture.
Lots of additional study materials including past exams appear on the Resources page.
Your course grade is computed using a point system with a total of 300 points, broken down as follows:
- Midterm Exam, worth 64 points
- Final Exam, worth 96 points
- Projects, worth 99 points
- Homework, worth 14 points
- Lab 0, worth 1 point
- Lab, worth 10 points
- Lab Participation, worth 8 points
- Discussion Participation, worth 8 points
There are a handful extra credit points throughout the semester, perhaps around 10, that are available to everyone.
Each letter grade for the course corresponds to a range of scores:
A+ ≥ 305 A ≥ 285 A- ≥ 270 B+ ≥ 250 B ≥ 225 B- ≥ 205 C+ ≥ 190 C ≥ 180 C- ≥ 175 D+ ≥ 170 D ≥ 165 D- ≥ 160
Your final score will be rounded to the nearest integer before being converted to a letter grade. 0.5 rounds up to 1, but 0.49 rounds down to 0.
There is no curve; your grade will depend only on how well you do, and not on how well everyone else does. Score thresholds are based on how students performed in previous semesters. Unlike some previous semesters you may have heard about, these thresholds will not be adjusted based on student performance.
These are the exact thresholds that will be used at the end of the course to assign grades. In a typical semester, about 60% of students taking the course for a letter grade will receive a B+ or higher.
Incomplete grades will be granted only for medical or personal emergencies that cause you to miss the final or last part of the course, only for students who have completed the majority of the coursework, and only if work up to the point of the emergency has been satisfactory. If you wish to discuss an incomplete in the course, please reach out to firstname.lastname@example.org or book an accommodations appointment as soon as possible.
Your lowest homework score will be dropped.
Each lab that you complete is worth 1 point, and you can receive a maximum of 10 lab points. There are going to be 12 non-setup lab assignments, so you can skip two and still get full credit. Lab 0 is not eligible to be skipped, as it is required to complete all future assignments.
The lab participation score is designed to make sure that all students attend at least the first few weeks of lab sections to try them out.
Attending a lab will earn you one lab participation credit. There will be about 12 possible credits available (Lab 0 does not count).
To earn a perfect lab participation score in the course, you need to earn at least 8 credits. Your course lab participation score is the number of lab participation credits you earn over the semester, up to 8. These are separate from the lab score component, which is graded based on lab completion and correctness.
The discussion participation score is designed to make sure that all students attend at least the first few weeks of discussion sections to try them out.
Attending a discussion will earn you one discussion participation credit. There will be about 12 possible credits available (Discussion 0 does not count).
To earn a perfect discussion participation score in the course, you need to earn at least 8 credits. Your course discussion participation score is the number of discussion participation credits you earn over the semester, up to 8.
This summer, we will be offering a full clobber for your midterm exam score, based on your final exam score. This means that if you score more points on the final exam than on the midterm, your score will be fully replaced by that better score. Clobbered scores are calculated as below:
def clobbered_midterm_score(your_midterm_score, your_final_score): clobbered_score = your_final_score * 64 / 96 return max(your_midterm_score, clobbered_score)
If you cannot turn in an assignment on time, you can request an extension—we guarantee we will grant 24-hour extensions for any non-extra credit assignment, no questions asked, and we will consider all other extension requests on a case-by-case basis. In absence of an extension, our policy is:
- Labs: We rarely accept late lab submissions.
- Homework: We rarely accept late homework submissions.
- Projects: Submissions within 48 hours after the deadline will receive 75% of the earned score. Submissions that are 48 hours or more after the deadline will receive 0 points.
We reserve the right to reduce grades by up to one full letter grade (e.g. from an A- to a B-) in the event of exceptionally rude or disrespectful behavior towards course staff or fellow students. This policy will only be applied in the case of behavior deemed explicitly harmful, derogatory, or discriminatory by the instructors, and would be used only extremely sparingly, but it exists to ensure that we can provide a safe and constructive learning environment for all students.
With the obvious exception of exams, we encourage you to discuss course activities with your friends and classmates as you are working on them. You will learn more in this class if you work with others than if you do not. Ask questions, answer questions, and share ideas liberally.
Learning cooperatively is different from sharing answers. You shouldn't be showing your code to other students or looking at others' code, except:
- During lab, you can share all you want as long as you're all learning.
- For a project that allows partners, you can share anything with your partner.
- If you've finished a problem already, you can look at others' code to help them finish.
If you are helping another student, don't just tell them the answer; they will learn very little and run into trouble on exams. Instead, try to guide them toward discovering the solution on their own. Problem solving practice is the key to progress in computer science.
Since you're working collaboratively, keep your project partner informed. If some medical or personal emergency takes you away from the course for an extended period, or if you decide to drop the course for any reason, please don't just disappear silently! You should inform your project partner, so that nobody is depending on you to do something you can't finish.
Any students caught collaborating on exams will receive an F in the course. Please don't be one of these students.
Reading others' homework or project solution to a problem before you solve that problem on your own will incur large point penalties. You are free to discuss the problems with others beforehand, but you must write your own solutions. The exception to this rule is that you may share code with your project partner.
If you are unsure if what you are doing constitutes academic misconduct, please clarify with the instructor or contact course staff. The following is a list of things you should NOT do. This list is not exhaustive, but covers most of the big offenses:
- Do not copy code from any student who is not your partner.
- Do not allow any student other than your partner to copy code from you.
- Do not copy solutions from online sources such as Stack Overflow, Pastebin, and public repositories on GitHub.
- Do not read others' solutions to an assignment before you have completed the assignment
- Do not post your solutions publicly during or after the semester.
If you find a solution online, please submit a link to that solution anonymously. When we find an online solution, we ask the author to remove it. We also record the solution and use it to check for copying. By reporting online solutions, you help keep the course fair for everyone.
In summary, we expect you to hand in your own work, take your own tests, and complete projects with code written only by you and your partner. The assignments and evaluations are structured to help you learn, which is why you are here.
Rather than copying someone else's work, ask for help. You are not alone in this course! The entire staff is here to help you succeed. If you invest the time to learn the material and complete the projects, you won't need to copy any answers.
A Parting Thought
Grades and penalties aren't the purpose of this course. We really just want you to learn. The entire staff is very excited to be teaching CS 61A this semester and we're looking forward to meeting such a large and enthusiastic group of students. We want all of you to be successful here. Welcome to CS 61A!