Technion - Israel Institute of Technology  
234247 - Algorithms 1
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Moed B appeals
The deadline for submitting moed B appeals is next Wednesday, 24.10.
Appeals should be submitted to Jonathan's cell on the 5th floor.
Use the formal appeal form ( ), along with a full copy of your exam. There is no need to print your draft notebooks.

Course staff.
Created on 15/10/2012, 12:17:54  
Moed C
Students who are eligible for a moed miluim exam, please contact Hadas by 15.10.
In your message, please include any form necessary for approval.

Course staff.
Created on 9/10/2012, 12:50:09  
Moed B grades published
The Moed B exams have been graded. A factor of +8 points has been given.
We will announce the deadline for appealing as soon as the exam scans will be available.

Course staff.
Created on 2/10/2012, 19:03:21  
Delay in Moed B grades
We're releasing this announcement in order to prevent you from waiting in expectation for the Moed B grades, and also to prevent any present or future physical damage done to F5 buttons.
Checking the Moed B might take longer than expected, since we're lacking staff. Our goal is to publish grades on Tuesday (2.10), hopefully sooner.
The Technion staff is currently on a two-week vacation that started on Tuesday, so either way the exam scans will only be available after the holiday.

We apologize for the delay.

Course staff.
Created on 27/9/2012, 12:49:49  
Wednesday's reception hours - time and place
Jonathan's reception hours tomorrow (19.9) will take place at Taub 7, hours: 11:00-13:00.

Course staff.
Created on 18/9/2012, 18:37:00  
Q&A before the Moed B exam (Piazza)
To compensate on the lack of reception hours before the Moed B exam (the Technion is closed most of next week), we are trying out a new service, called Piazza, to answer questions you have before the exam.
Basically, each student can publish questions on the Piazza course website.
Each question can have two answers:
1. Course staff answer.
2. Answer given by the students. Every student can edit this answer, similar to Wikipedia.
If we (the "Instructors") think the answer given by you is good, we can approve it.
At the bottom of each question is a discussion section for follow-up questions.

To log on to our course's Piazza website, enter:
(There was no Spring 2012 option, so Summer 2012 was the closest option :))
Choose "Student" and click "Add classes" at the bottom of the page.
Log in using your @t2 account.

Before posting, please read the pinned announcement called "Please read before posting" (what a surprising name for this announcement!).
To prevent duplicates, please search for an existing answer before publishing a new question.

Good luck,
Course staff.
Created on 12/9/2012, 18:27:24  
Moed B exam
Date: Thursday 20.9, 17:00-20:00.
Rooms: Taub 4-9.

The cover page will be identical to the one used for the Moed A exam.
Please pay attention to the following notes:
1, There are 5 questions in the exam, 4 pages in total.
2. The exam is an anonymous exam.
Do not write your names on any of the pages you will receive.
Instead, you are required to write your ID number twice (on the usual cover page given by Ulmann and on the course's cover page mentioned earlier).
Please make sure that your ID number is written clearly.
3. You are allowed to bring a single A4 page written on both sides. No additional material is allowed.
4. The exam will contain a question from your homework assignments.

Reception hours before the exam:
Hadas: Thursday (13.9), 12:30-13:30, Taub 623.
Jonathan: Wednesday (19.9), time and room to be announced.

Good luck,
Course staff.
Created on 11/9/2012, 22:39:22  
Moed A appeals
The moed A appeals have been checked and returned, the updated grades appear on the website.
You can receive your appeal at the secretaries' office.

Course staff.
Created on 6/8/2012, 15:30:48  
Moed A grades published
The Moed A exams have been graded. A factor of +12 points has been given.

Some few notes:
1. The ExamA column is your rounded grade, not your actual grade.
Because of the "Don't know" option, some of the exam grades are fractional.
The actual grade is written on the front page of your exam solution.

2. Only 101 students (nearly half the course) participated in the exam.
We are well-aware of the reasons behind your decisions, yet we had to take them into account when setting the final grades.

One of the most important statistic that is not published on the GR website is the following:
Participating students gained, on average, 68% of the points in question 2, the question taken from your homework assignments.
This is very low. Independent on how difficult an exam is (and we believe the Moed A was more than fair), the HW question should be the bread & butter of the exam - a piece of cake, considering the fact that we have worked all the semester towards this.
To those of you planning on taking the Moed B, keep this in mind.

3. Appeals should be submitted to Jonathan's cell on the 5th floor no later than 31/7.
An appeal should contain a formal appeal form ( ), along with a full copy of your exam (no need to print your draft notebooks).

We wish you all good luck with your remaining exams and a hope you enjoy your summer vacation,
Course staff.
Last updated on 18/7/2012, 21:07:58  
Auxiliary claims
A list of additional auxiliary claims, that can be used without proof during the exam, has been published under the "Course Material" tab.

Course staff.
Created on 8/7/2012, 20:12:14  
Solution to a dynamic programming question
The solved questions file appearing under the "Course Material" tab has been updated and now contains a solution to a question on dynamic programming.
If you still see the old file, try reopening your browser.

Course staff.
Created on 8/7/2012, 03:22:24  
Reception hours on Sunday
Unless stated otherwise, the reception hours on Sunday (7.7) will take place at Taub 2.
In case of any last minute change, we will stick an announcement on the door to Taub 2.

Course staff.
Created on 7/7/2012, 23:21:07  
Reception hours before the exam
Alex: Wednesday (4.7) 18:30-19:30, Taub 227.
Hadas: Thursday (5.7) 14:00-15:00, Taub 623.
Jonathan + Omri: Sunday (8.7) 10:30-12:30, room will be announced later on.

Course staff.
Created on 3/7/2012, 17:06:19  
Questions with official solutions
We have uploaded a file containing 5 questions with full explained solutions.
You can find the file under the "Course Material" tab.

A bit about the file:
1. First, we apologize for this being uploaded relatively late.
On an honest note, we believe that this may help you not only understand the material, but also see what is expected from you and how to write solutions to questions.
The idea of having such a file came up during conversations between students and us.
As some of you pointed out, since the only feedback you have received this semester has been live feedback, such a file is essential and we agree.
Your feedback is important to us.

2. Due to lack of time from our end, we haven't covered one topic (dynamic programming).
This will be completed in the next few days, stay tuned.

3. If you find any errors, please let us know. We will be happy to add a thank you note with your name on it.
(Well, unless you want to stay anonymous and not let everyone find out who's responsible for screwing up the factor...)

Course staff.
Created on 2/7/2012, 12:19:52  
Moed A exam
Date: Monday 9.7, 9:00-12:00.
Rooms: Ulmann 301-305,307,309.

The cover page of the exam can be found under the "Course Material" tab.
Please pay attention to the following notes:
1, There are 5 questions in the exam, 5 pages in total.
2. The exam is an anonymous exam.
Do not write your names on any of the pages you will receive.
Instead, you are required to write your ID number twice (on the usual cover page given by Ulmann and on the course's cover page mentioned earlier).
Please make sure that your ID number is written clearly.
3. You are allowed to bring a single A4 page written on both sides. No additional material is allowed.
4. The exam will contain a question from your homework assignments.

Reception hours before the exam will be published tomorrow.

Good luck,
Course staff.
Last updated on 2/7/2012, 11:47:58  
Next week's workshops - Changes + Complete updated list.
The following two changes apply for next week's lessons:
1. Omri's tutorial and workshop hours are cancelled. Instead, Omri will give a complementary workshop on Sunday (24.6), 18:30-20:30, at Taub 401.
2. Jonathan's workshop on Sunday (24.6), 16:30-18:30, has also been moved to Taub 401.
3. Just in case you forgot, there will be no lectures next week.

Complete set of workshop hours:
Sunday (24.6):
- 13:30-14:30, Taub 3.
- 16:30-20:30, Taub 401.
Monday (25.6):
- 15:30-16:30, Ulman 309.
- 18:00-20:00, Taub 701.
Tuesday (26.6):
- 9:30-10:30, Ulman 304.
- 14:30-16:30, Taub 601.

Course staff.
Created on 23/6/2012, 20:35:16  
Classes next week
Next week we will not hold any lectures.
As stated in a previous announcement, instead of the tutorials we will hold additional workshop hours, in the same rooms as the recitations are usually at.
The usual workshops will also be held.

Course staff.
Created on 19/6/2012, 13:10:51  
HW6 update
We have taken out one of the clauses in question 2.
The PDF file has been updated.

Course staff.
Created on 17/6/2012, 17:40:18  
HW6 published + Tutorials until the end of the semester
The last assignment on flow networks has been published.
Starting next week, the workshops will focus on this assignment.

Next week (17.6-21.6) we will hold the last tutorial, also on flow networks.
During the final week (24.6-27.6) we will not hold tutorials. Instead, we will give additional workshop hours in the same classrooms.

The assignment contains 6 questions instead of 5.
It is slightly longer than usual, but we believe that instead of giving you another tutorial on flow networks (last week of the semester), a better approach in this stage would be to let you solve questions and discussing your solutions in class.

Good luck,
Course staff.
Created on 14/6/2012, 12:29:23  
HW5 - Clarification to question 1
We have added a clarification to question 1 on what is a matching.
Please notice that the homework assignments have corresponding FAQ sections, so make sure you take a look from time to time.
The added explanation appears both in the PDF file and in the FAQ section.

Course staff.
Created on 3/6/2012, 13:00:11  
HW5 published
The fifth homework assignment on greedy algorithms (continued) and dynamic programming has been published.
We recommend you complete it before 14.6.
Starting next week, the workshops will focus on HW5.

Course staff.
Created on 30/5/2012, 19:04:06  
Ran's complementary tutorial today for Sunday's group - room
Ran will give a complementary tutorial today (13:30-14:30) at Taub 3.
The recitation given today will be recitation 10 - first tutorial on Dynamic Programming.

Course staff.
Last updated on 30/5/2012, 02:09:18  
Next week's lessons and workshops
Ran will hold a complementary tutorial for Sunday's group on Wednesday (30.5), 13:30-14:30.
We will announce the room next week.

Jonathan will give a workshop on Tuesday (29.5) 16:30-18:30, Taub 701.
This replaces his usual workshop on Sunday.

Course staff.
Created on 24/5/2012, 15:56:42  
Complementary tutorial today - room
The complementary tutorial for Alex's group will be given today (15.5), 16:30-17:30, at Taub 201.

Course staff.
Created on 15/5/2012, 08:17:14  
Small correction in recitation 8 slides
The last slide of recitation 8 has been corrected.
Please make sure you print out the updated version.

The two tutorial groups who have already seen this tutorial will see the updated slide next week again.
We apologize for the extra work on your end.

Course staff.
Created on 14/5/2012, 17:14:07  
HW4 published
The fourth homework assignment on shortest paths and greedy algorithms (part 1) has been published.
The assignment may appear longer than usual on first sight (6 questions), but it was actually written this way to make it simpler. Honestly.
Following the announcement on HW3, we recommend partying during the student festival.

Starting next week, the workshops will focus on HW4.

Course staff.
Created on 14/5/2012, 00:04:18  
Tuesday's recitation and workshop this upcoming week
This week there is a missing Tuesday, due to the student festival and the Technion calender (Tuesday is "Matkonet" Thursday).
Since we cancelled a tutorial before Independence Day, we are giving a complementary tutorial this week for Tuesday's group.

The complementary tutorial will be given on Tuesday (15.5), 16:30-17:30.
The room will be announced beforehand.

The workshop scheduled for Tuesday will take place as usual (14:30-16:30, Taub 601).

Course staff.
Created on 12/5/2012, 23:37:08  
Correction in recitation 6 (Important)
The solution to the second question given in recitation 6 was slightly incorrect.
Please read the following explanation:

In question 2 of recitation 6, we were given a graph G=(V,E), a weight function w:E->R and an MST of the graph T.
The question dealt with a new weight function w':E->R, in which the weights of the b heaviest edges (denoted by B) have been increased.

Our first claim was that there exists a sorted order w(e_1) <= ... <= w(e_m) of the edges, such that running Kruskal on it gives us T.
The incorrect claim was that the group B was the last b edges of the sorted order.
Since edge weights could have been equal, it was possible that edges in B would have appeared elsewhere in the sorted order.

To make as few changes as possible to the existing solution, we have added an additional assumption that w:E->R gives different weights to edges.
Given this, we can assume that the edges in B are the last m edges in the sorted order matching T.

Please go over the corrected solution before solving the third HW assignment.
We sincerely apologize for giving out the incorrect solution and thank those who pointed out this mistake.

Course staff.
Created on 3/5/2012, 16:28:49  
HW3 published
The third homework assignment on Minimum Spanning Trees (MST) has been published.
We recommend you complete it before the student festival (17.5).
Starting next week, the workshops will focus on HW3.

Course staff.
Created on 29/4/2012, 12:37:55  
Today's workshop - room
The workshop today (Monday 14:30-16:30) will be held in Taub 601.

Course staff.
Last updated on 23/4/2012, 07:28:42  
Next week's lessons and workshops
In order to keep the tutorials synchronized with the lectures, all of the recitations next week are cancelled.
These recitations will be completed later on during the semester.

We will hold two workshops next week:
- Sunday 16:30-18:30 (Taub 601)
- Monday 14:30-16:30 (room will be announced next week).

These workshops are additional DFS tutorials, as some of you asked us to give.
Specifically, the workshops during the week after next week (29/4 - 3/5) will also be on DFS.

The next homework assignment on MSTs will be published next week, for those who would like to work on it sooner.

Course staff.
Created on 20/4/2012, 14:11:41  
Today's lecture - room change
The lecture today (12:30-14:30) will take place at Ulman 707.
We apologize for the sudden announcement, we were equally surprised.

Course staff.
Created on 16/4/2012, 10:47:31  
Change of class: Thursdays tutorial group
Starting this week (19.4), Ran's recitation on Thursdays (09:30-10:20) will take place in Taub 4.

Course staff.
Created on 15/4/2012, 15:00:51  
Change of class: Monday's tutorial group
Jonathan's tutorial on Monday will be given at Ulman 309 for the rest of the semester.

Course staff.
Created on 15/4/2012, 14:39:31  
HW2 published
We have uploaded the second homework assignment on DFS and Strongly Connected Components, for those of you who would like to work on it during the vacation.
For those who are concerned about the rest of their vacation, you can ignore this announcement until next week.
The workshops between 15/4 - 27/4 (the two weeks after the Passover vacation) will be dedicated to this assignment, so you will have plenty of time to complete it once the vacation ends.

Enjoy *
Course staff.

( * ... solving the homework assignment. What, you really thought we meant enjoy the vacation? :P )
Last updated on 8/4/2012, 12:56:29  
Wednesday change of classrooms
Due to a faculty event taking place this Wednesday (4/4) inside the Taub building, the following classes have been moved to a different location:
- Lecture (14:30-16:30) - Ulman 503
- Tutorial (16:30-17:30) - Ulman 307
- Workshop (17:30-19:30) - Taub 401

Course staff.
Created on 2/4/2012, 12:30:24  
We've opened a FAQ section for the first homework assignment.
The recommended completion date for the assignment is 5.4.2012 (instead of 1.4 as previously stated).

To clarify, next week's workshops will refer to HW1 and will be identical to last week's workshops.

Course staff.
Created on 29/3/2012, 18:02:03  
One-time change of hours of Sunday's workshop
Jonathan's workshop this Sunday (25.3) will take place during the hours of 14:30-16:30 (instead of 16:30-18:30 as usual) at Taub 601.

Course staff.
Created on 23/3/2012, 16:10:05  
Change of class: Wednesday's tutorial group
Starting next week (28.3), Omri's recitation on Wednesdays (16:30-17:30) will take place in Taub 4.

Course staff.
Created on 21/3/2012, 16:33:01  
List of workshops in Algorithms
We have published workshop hours ("Sadna'ot"), which will be dedicated to the homework assignments.
You can find them under the "Staff" button on the left. For your convenience, we give this list of workshops here:
- Jonathan: Sunday 16:30-18:30, Taub 601
- Ran: Monday 18:00-20:00, Taub 701
- Alex: Tuesday 14:30-16:30, Taub 601
- Omri: Wednesday 17:30-19:30, Taub 4

The workshops will start next week and change on a 2-week basis.
For example, all 8 workshops given by us in the following 2 weeks (starting this Sunday) will all be identical and refer to the first homework assignment.
Thus, you should make sure to attend one workshop in the next 2 weeks.

Every workshop will be divided into 3 parts:
1. Individual questions (~40 minutes): You will be able to ask us individual questions regarding the assignment.
The purpose of this part is for you to receive personal assistance regarding the assignment, and to allow you to continue thinking after we give you hints and directions.

2. Class solutions (~40 minutes): In this part, all of the participating students along with the teaching assistant will discuss the questions and solution approaches.
The purpose of this part is to give you the tools needed to understand the homework assignment and its solution.

3. Individual proofs (~40 minuts): In the final part, you will be able to choose one (or more) claims needed in order to prove the correctness of one of your algorithms, write it down and receive instant feedback from us.
We will give you remarks on-the-spot on the correctness of your proof. This section is also individual.

Try to solve the assignment before attending a relevant workshop.

Good luck,
Course staff.
Created on 21/3/2012, 16:30:25  
HW1 published
The first homework assignment is now available on the website.
We remind you that homework assignments in this course are not mandatory. However, we highly recommend solving them fully, as they play a very important part in understanding the material.
We note that ~15% of the final exam will consist of a question from the homework assignments, if all of our motivational speeches up to now weren't enough.

Course staff.
Created on 21/3/2012, 16:29:02  
New tutorial class
An additional tutorial class has been opened.
This tutorial will be held on Sundays 13:30-14:30, and will be given by Ran at Taub 3.

Course staff.
Created on 10/3/2012, 18:54:26  
Welcome to Algorithms 1! (234247)
This is the first mail from the Algorithms 1 course staff.
Each student registered to the course should have received this email. If you haven't, you are either unregistered or do not appear on the mailing list.
To add yourself to the mailing list, use the "Auto Update" button on the menu to the left.

Information regarding the course can be found under the "Syllabus" tab.
Please read the course Syllabus file, as it contains important guidelines and instructions.
A full course schedule will be uploaded soon.

Under the "Course Material" tab you can find recitation summaries and the slides we will use throughout the course.
We highly recommend printing these slides and coming with them to class.

Both lectures and recitations will be held starting this week.

Wishing you all a good semester,
Course staff.
Last updated on 10/3/2012, 18:52:56