COS 226 Midterm Information, Fall 2025
DATE, TIME, and ROOM
-
The exam is 10:40am–12pm on Tuesday, October 7.
You will have 80 minutes to complete the exam.
-
You must take the exam in the assigned room.
Be sure to go to the room corresponding to the precept in which you are
officially enrolled, even if you have attended a different precept.
- Friend Center 101: P02, P02A, P02B, P03A, P03B
- Maeder Hall 002: P01, P01A, P04
-
If you have been approved for special accommodations by
ODS, you will take the exam
in accordance with your approved accommodations in a separate room.
Please contact Kobi
Kaplan as soon as possible to coordinate.
-
If you believe you will not be able to take the exam during
this period for any reason,
please contact
Kobi Kaplan
as soon as possible.
However, exam postponements are offered only for extraordinary circumstances;
in such cases, you must get both the recommendation of a residential college Dean and course staff approval.
FORMAT
The exam will be administered in-person, on paper.
The exam is preprocessed by computer.
- Write neatly, legibly, and darkly.
- Put all answers (and nothing else) inside the designated answer spaces.
- Fill in bubbles and boxes completely.
- To change an answer, erase it completely and redo.
- You may use pencil or pen, but we recommend pencil so that you can fix mistakes.
- We will provide scrap paper.
RULES
- The exam is governed by Princeton’s Honor Code for in-class exams.
- The exam is closed book, closed notes.
- You may bring one reference sheet (8-5-by-11 paper, one side)
with notes in your own handwriting to the exam.
(You may not write the reference sheet digitally and then print it, say with a tablet and stylus.)
- No electronic devices are permitted, including calculators. Turn off your cell phones.
- No communication during the exam is permitted (except with a staff member to ask a clarification question).
- Discussing the contents of this exam before solutions have been posted is a violation of the exam rules.
EXAM MATERIAL
The exam covers lectures 1–10
and programming assignments 1–3
and the following sections from the textbook Algorithms, 4th edition:
| Section | Excluded Topics |
|---|
| § 1.3 | - |
| § 1.4 | - |
| § 1.5 | - |
| § 2.1 | Shellsort |
| § 2.2 | - |
| § 2.3 | - |
| § 2.4 | IndexMinPQ |
| § 2.5 | - |
| § 3.1 | - |
| § 3.2 | Deletion |
| § 3.3 | Deletion |
MIDTERM EXAM REVIEW
- A good way to practice for the final exam is to solve problems from
old exams.
Since the material has evolved over the years, here is a list of questions that are still relevant to the current course materials:
- Spring 25: all questions
- Fall 24: all questions
- Spring 24: all questions
- Fall 23: all questions
- Spring 23: all questions
- Fall 19: 1, 2, 3, 4, 5, 6 (except last 2 options), 7, 8, 9
- Fall 18: 1, 2, 3, 4, 5, 7, 8, 9
- Fall 17: 1, 2, 3, 4, 6a, 6b, 7, 8, 9
Solutions to some of the design problems in older exams might
mention hash tables. In the questions listed above you can always
replace a hash table with any efficient symbol table, like a balanced
binary search tree. Note that operations involving a balanced binary
search tree will take O(log n) time instead, whereas operations
involving hash tables will take O(1) time under certain technical assumptions
(you will learn about hashing in the second half of the course).
- Check the office hours schedule on the course Help page.
Feel free to bring questions,
listen in on other students asking questions, or a combination of the two.
Good Luck!