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.

  1. 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.
  2. CS 61B deals with the more advanced engineering aspects of software, such as constructing and analyzing large programs.
  3. CS 61C focuses on machines and how they execute the programs you write.

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 examine the Scheme programming language as well as the Structured Query Language in the latter half of the course.

Mastery of a particular programming language is a very useful side effect of CS 61A. However, our hope is that once you have learned the essence of programming, you will find that picking up a new programming language is but a few days' work.


Math 1A is a corequisite for CS 61A. (That is, it may be taken concurrently.) Math 10 or Math 16A are also fine.

There is no formal programming-related prerequisites for admission to CS 61A, but that doesn't mean that it's the right first course for all students. Many CS 61A students have had significant prior programming experience, but many do not. Students without prior experience typically spend a huge amount of time each week on the course.


If you don't feel ready for CS 61A, we recommend that you take one of these courses first. You can always enjoy CS 61A in a future semester.

  • CS 10: The Beauty and Joy of Computing, which provides a bird's-eye-view of the field of computer science. The course teaches students how to program using Snap (based on Scratch), one of the friendliest programming languages ever invented and Python, which we use in this course. But the course is far more than just learning to program! You'll also learn about some "Big Ideas" of computing, such as abstraction, design, recursion, concurrency, simulations, and the limits of computation. You'll also see some beautiful applications of computing that have changed the world, as well as talk about the history of computing and where it will go in the future.
  • Data 8: The Foundations of Data Science is an introduction to data science designed to be accessible for all Berkeley students. The course 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. The overlap between Data 8 and CS 61A is small, but the programming skill you will acquire in Data 8 will prepare you for the fast pace of CS 61A.

Course Format

The course includes many events and opportunities for learning: lecture, lab, discussion, office hours, group mentoring, and one-on-one tutoring. Weekly lab and discussion sections are typically the most valuable events to attend. For the rest, your attendance is optional. These events exist to help you learn, and so you are advised to attend as many as required to master the material.

Lecture: There are four 90-minute lectures per week everyday Monday through Thursday in 2050 Valley Life Sciences Building. Slides will be posted the night before each lecture.

Lab and Discussion Sections: There are two lab and two discussion sections each week. 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.

You are encouraged to attend a matching lab and discussion section taught by the same TA. If you wish to switch sections, simply start attending the section you wish to join. We are often able to accommodate these wishes, although seating priority will be given to people who are officially enrolled in that section. You do not need to officially update your section on CalCentral.

It's best to find a permanent section by the end of the first week because we have seen that sticking with one TA and one group of students creates a more close knit learning environment!

Office Hours: Attending office hours is another excellent way to succeed in this course. You can ask questions about the material, receive guidance on assignments, work with peers and course staff in a small group setting, find project partners, and learn about computer science at Berkeley.

Group Mentoring Sections: Optional group mentoring sections are held each week. Each section is run by a course tutor or academic intern and feature worksheets that cover selected topics in the course. These sections of at most 4 or 5 students meet twice a week and are here to create a stronger feeling of community in the class and reinforce conceptual understanding of course material. The course tutors are not prepared to answer questions about assignments, so they won't be able to answer questions about labs, homeworks, or projects.

We expect to have enough group mentoring sections to serve roughly one-third of the class. Sign-ups begin the week before classes start.

One-on-One Tutoring: Like group mentoring sections, one-on-one tutoring is a new service we're piloting this semester to offer students more individual support with course content. Each week, you may sign up for a one-hour long individual tutoring session. Since tutoring is offered by course tutors, they won't be able to answer questions about course assignments.

One-on-one tutoring sign-ups will be released every Thursday at 1 pm after lecture and are available on a first-come, first-served basis. Tutors will select students whose availability best matches their schedule and contact you directly by email. You will then have 24 hours to respond to their email. If you do not respond within 24 hours, the tutor will find someone else to help instead.


Each week, there will be problems assigned for you to work on, most of which will involve writing, debugging, and discussing 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 on your own time before the scheduled due date. Lab exercises are graded on completion. You will get full credit for reasonable effort so long as you make good progress on all the problems.

There will be two lab assignments each week, each worth two points. There are 15 lab assignments in total, 3 of which are ungraded exam review labs. Of the remaining 12 graded labs, we will drop your two lowest lab scores over the course of the semester. Labs account for a total of 20 points.


Homeworks are meant to illustrate and explore new topics. You are encouraged to discuss the homework with other students, as long as you write your own code and submit your own work. The purpose of homework is for you to learn the course material, not to prove that you already know it. Therefore, homework is not graded on the correctness of your solutions, but on effort. You will get full credit for reasonable effort so long as you make good progress on all the problems.

There will be 10 graded homework assignments each worth three points. We will drop your lowest homework score over the course of the semester. In addition to the graded homework assignments, there are also 3 homework surveys each worth one point. Completion of all three surveys can make up for one additional homework assignment. Homework thus accounts for a total of 30 points.


Projects are larger assignments intended to combine ideas from the course in interesting ways. The first two projects will be done individually; the last two in groups of two students, but some of the work is split up so that each problem is done by one student. You must work together to ensure that both group members understand the complete results. You are encouraged to complete projects in pairs; your partner can be anyone else enrolled in CS 61A. We recommend finding a partner in your section. Your TA will help. You may also work alone, although this is not recommended.

There will be four projects, for a total of 100 points. Projects are graded on correctness, as well as for code composition (i.e. code clarity and legibility).


During every lab section, academic interns will run check-offs for homework and lab assignments. These will consist of them asking you a few short questions meant to assess your understanding of the material. If you made mistakes on the assignment but later reviewed the solutions, you will know enough to answer.

Each week, you must choose to check off at least one of the week's homework or lab assignments during lab. Check-offs are worth one point of the week's total assignment score. Therefore, if you fail to get checked off for the week, one point will be deducted from your overall grade. To reduce administrative overhead, please try to attend the same lab section each week for your check-off. Check-offs on lab assignments will not ask questions on the optional questions.

Check-offs are a great opportunity to get one-on-one feedback and gain a deeper understanding of the material, so you are welcome to check off multiple assignments each week. However, you are only required to check off one assignment per week, and checking off more than one will not earn you any additional points.


The midterm exam will be held on Thursday, July 13 from 5-8 pm. You are permitted to bring two double-sided, letter-sized, handwritten cheat sheet.

The final exam will be held on Thursday, August 10 from 5-8 pm. You are permitted to bring four double-sided, letter-sized, handwritten cheat sheets.

If you have a conflict with either exam, you must let us know by the first week of the course. We may be able to offer an alternate exam time. Additional exceptions will only be made for extraordinary circumstances.

More exam details will be released as the exam approaches.

Recovery Points

We understand that exams may not be entirely indicative of your efforts in the class. For this reason, you may earn back a certain number of points for each exam based on your participation in discussion sections. Therefore, participation is not required, but it is tracked and potentially beneficial.

Participation is tracked by submitting a short quiz during each discussion section on that day's material. The purpose of this quiz is not to stress you out but to give you feedback on how well you've mastered the material so it is graded on effort rather than correctness.

  • Midterm Participation: Discussions 1-6, totaling 5 (No discussion 4)
  • Final Participation: Discussions 8-14, totaling 7

We calculate your recovery points using the following logic:

def recovery_points(your_score, discussions, max_exam_score, max_discussions):
    if discussions == 0:
        return 0
        half_score = max_exam_score / 2
        max_recovery = (half_score - your_score) / 2
        return max(0, max_recovery * discussions / max_discussions)

This means if you score over 35 points on the midterm or 40 points on the final, your score remains the same. The more you participate in discussion, the more points you can earn back. If you score below that threshold, you have the chance to recover a few points. If you score far below the threshold, you will recover many points. This is our policy for ensuring that everyone who puts in a lot of effort into the class will have a very high chance of passing. See the graph generated for details.



The online textbook for the course is Composing Programs, which was created specifically for this course. Readings for each lecture appear in the course schedule. We recommend that you complete the readings before attending lecture.

We may occasionally differ from the material found in Composing Programs. As a result, we recommend the lecture notes, labs, and discussion handouts as your primary source of information.

Computing Resources

If you are enrolled in the class, you may request a CS 61A instructional account. This will allow you to use any EECS instructional lab computer in Soda or Cory Hall. You may use any lab you wish, as long as there is no class using the space.

Be respectful of the lab space. Please don't steal the chairs, and definitely do not eat or drink in the lab. Don't unplug anything; unplugged computers make our hard-working instructional computing team very sad. If you see someone disrupting the space, ask them to stop.

Labs are normally available for use at all times, but you need a card key for evening access. If you are a Berkeley student, your student ID will automatically grant you access to the Soda second floor labs. Otherwise, you can fill out an application from 387 Soda (the front desk).

DSP Accommodations

If you are enrolled in DSP and would like an accommodation, please email cs61a@berkeley.edu. We will post detailed information on Piazza as the semester progresses for critical matters such as scheduling an alternate exam time.


If it were up to us, we wouldn't give grades at all. Since we can't do that, the grading policy of the course has these goals: it should encourage you to do the coursework and reward reasonable effort with reasonable grades; it should minimize competitiveness and grade pressure, so that you can focus instead on the intellectual content of the course; and it should minimize the time we spend arguing with students about their grades. To meet these goals, your course grade is computed using a point system with a total of 300 points. Half of those points will come from assignments; the other half will come from exams.

  • Labs, worth a total of 20 points.
  • Homework, worth a total of 30 points.
  • Projects, worth a total of 100 points.
  • Midterm, worth 70 points.
  • Final, worth 80 points.

Each letter grade for the course corresponds to a range of scores:

A+  ≥ 294    A  ≥ 283    A-  ≥ 275
B+  ≥ 260    B  ≥ 240    B-  ≥ 230
C+  ≥ 220    C  ≥ 210    C-  ≥ 200
D+  ≥ 190    D  ≥ 180    D-  ≥ 170

Notice that this scale is nonlinear; the steps are wider in the B range.

This grading formula implies that there is no curve; your grade will depend only on how well you do, and not on how well everyone else does.

Incomplete grades will be granted only for dire medical or personal emergencies that cause you to miss the final, and only if your work up to that point has been satisfactory.

Late Policy

If you cannot turn in an assignment on time, contact your TA and partner as early as possible. Depending on the circumstance, we may grant extensions.

  • Labs: We will not accept any late lab submissions. Your two lowest lab scores will be dropped. Lab exercises are graded on completion.
  • Homeworks: We will not accept any late homework submissions. Remember that homework is not graded on the correctness of your solutions, but on effort. You will get full credit for reasonable effort so long as you make good progress on all the problems.
  • Projects: Submissions that are within 24 hours after the deadline will receive 75% of the earned score. Submissions that are 24 hours or more after the deadline will receive 0 points.

Learning Cooperatively

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 definitely learn more in this class if you work with others than if you do not. Ask questions, answer questions, and share ideas liberally.

Working cooperatively in groups is a change from the traditional approach in schools, in which students work either in isolation or in competition. But cooperative learning has become increasingly popular as educational research has demonstrated its effectiveness. One advantage of cooperative learning is that it allows us to give intense assignments, from which you'll learn a great deal, while limiting the workload for each individual student. Another advantage, of course, is that it helps you to understand new ideas when you discuss them with other people. In the past many students have commented that they didn't really understand the course until they worked as academic interns and explained the ideas to later students.

Since you're working collaboratively, keep your project partner and TA 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.

Online Forum

If you have any questions, please post them to Piazza, the course discussion forum. Piazza allows you to learn from questions your fellow students have asked. We encourage you to answer each others' questions!

Piazza is the best and most reliable way to contact the course staff. You are also welcome to email the instructors or your TA directly.

Academic Honesty

Cooperation has a limit, and in CS 61A that limit is sharing code. You are free to discuss the problems with others beforehand, but you must write your own solutions. The only student with whom you can share code is your project partner.

Since this may be your first computer science class, exactly what constitutes as cheating might be unclear. If you are unsure if what you are doing is cheating, please clarify with the instructors or TAs. 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 or post your solutions publicly. This includes websites such as Stack Overflow, Pastebin, and public repositories on GitHub (you are welcome to use private repositories).

If you find a solution online, please submit a link to that solution. 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 your own projects. The assignments and evaluations are structured to help you learn, which is why you are here. The course staff works hard to put together this course, and we ask in return that you respect the integrity of the course by not misrepresenting your work.

If you are found to be cheating in this course, we will always ask you to come in and discuss the situation and give you a chance to explain. The first offense results in a negative score for the assignment. If you are found to be cheating a second time, we will not hesitate to fail you, report you to the center for student conduct, and then also call your parents. Detecting copied assignments is very easy for our computers, so please don't try!

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 summer, and we're looking forward to having such a large and enthusiastic group of students this semester. We want all of you to be successful here. Welcome to CS 61A!