Posted by: atri | August 9, 2014

Fall 2014

Again, we won’t be using this blog for the course.

Posted by: atri | August 14, 2013

Dormant for Fall 2013

We will not be using the blog for Fall 2013 version of CSE 331. Currently, the blog is serving an archival purpose only.

Posted by: atri | December 23, 2012

I just submitted the final letter grade on HUB. I’m not sure when you guys can see the letter grade on HUB but just double-check to make sure it matches the one on UBLearns. (I double checked my data entry but it never hurts to check again just in case.)

Below the fold are the jokes from the final exam: enjoy!

I enjoyed having y’all in the class this fall: hope you guys had fun too. Feel free to stop by office to chat in the future if you want. Have a great holiday break!

Posted by: atri | December 19, 2012

I will submit the final letter grades on Saturday, so if you find any inaccuracies in any of your scores on UBLearns, please let me know by Friday. Unless there is a totaling mistake, we will not entertain any regrading requests on anything except the final exam and HW 10. Again all of these should be done by Friday.

Given all your scores (which you can find on UBLearns), here is how you can calculate your grade:

1. Add up your 7 best homework scores (i.e. drop the lowest three) to get the number $\mathrm{H}$, which is at most $700$. (Note that if you submitted a homework late, then it would be counted as a $0$.)
2. Your midterm score $\mathrm{M}$, which can be at most a $100$. (Do not add the bonus points.)
3. Your final exam score $\mathrm{F}$, which can be at most a $100$. (Do not add the bonus points.)
4. Compute the exam component of your grade as $\mathrm{E}=\max(0.3\times \mathrm{M}+0.4\times\mathrm{F},0.7\times \mathrm{F})$.
5. Your class participation score $C$, which can be at most a $5$ and is the sum of your mini project and piazza participation part. To see your scores on the latter, check UBLearns.

Your total score $T$ out of a $100$ can be computed by the following formula:

$T=\frac{\mathrm{H}}{28}+\mathrm{E}+\mathrm{C}$.

Check your $T$ score with the table below. (Just to be sure, I have also uploaded the score $T$ on UBLearns.)

• $\ge 90$: A
• $<90, \ge 76$: A-
• $< 76, \ge 66$: B+
• $< 66, \ge 63$: B
• $<63, \ge 57$: B-
• $<57, \ge 54$: C+
• $< 54, \ge 47$: C
• $<47, \ge 41$: C-
• $< 41, \ge 33$: D+
• $< 33, \ge 29$: D
• $< 29$: F

Please don’t come to me and argue about the boundaries: in a few cases the boundaries are clear but in most cases, they had to drawn somewhere.

Have a good break!

Posted by: atri | December 18, 2012

The final exam has been graded. There is a fair amount of information in this post, so please read through carefully.

1. Your total score on the final exam has been uploaded to UBLearns.
2. You can pick up your final from Diane in the CSE main office. You will need to show her your UB card to pick up the final. (In case you do not know where Diane sits, you can get to her desk as follows: if you are going towards Jaynee’s office in the long corridor from the elevators, then Jaynee office is the last door on the left. Diane’s is the door on the left just before Jaynee’s.) You can pick up your final during normal office hours starting tomorrow, Wednesday, Dec 19.
3. I will be in my office from 2-5pm on Thursday, Dec 20 in case you have any questions on the final grading. (However, please go through the rubric below first.) In case you cannot make it during that time, you can email me a scanned copy of the part of the final that you have a question with. Please note: Re-grading requests will only be entertained if there is some obvious mistake (e.g. a totaling mistake)– please do not quarrel about the rubric: it was the same for everyone.
4. My plan is to get the rest of the grading (mini project, piazza, overall letter grade) done by tomorrow, Wed, Dec 19. I’ll put up  blog post(s) once I have done so.
5. The graded finals have solution sketches written on them in case you’re interested in the solutions.

The rest of the post is specific to grading.

The stats are as follows:

• Mean: 48.1
• Median: 53

Below is the grading rubric that was used for the different questions. As usual these are general guidelines. Things might change slightly for specific cases.

2. 0/6 if the T/F answer is incorrect (irrespective of the justification). As mentioned in the exam: 2 points were for the T/F answer and 4 points were for justification. As a general rule: a justification that was incorrect/had no real information would get 0/4; a half-way correct justification would get 2/4. Below are more details for the specific parts:
1. Mention GS algorithm runs in $O(N)$ or $O(n^2)$ or it’s linear are fine. Fail to mention or fail to distinguish $n$ and $N$ will lead a deduction of 4 points.
2. Mention linear scan or $O(n)$ scan will get full points. Listing the procedure but not mention what kind of scan will get a deduction of 1 point.
3. You should clearly state how long it takes to shift and do summation, otherwise you will get a deduction of 2 points each for not correctly stating shift and summation time.
4. All 4 points deducted if answers says binary search without specifying how one gets an upper bound on $n$.
5. This question a easy if you know what $M[s,n-1]$ is. If you state the meaning of it, you will get full points. If you state nothing about $M[s,n-1]$ but something else that is not wrong, you will get a deduction of 3 points. In other cases, your points depend on how much your statement related to the meaning of $M[s,n-1]$.
• 15/25 is for algorithm.
• 7/25 is for correctness.
• 3/25 is for running time.

There are two common approaches to solve Q3.The first one is greedy strategy by picking golds as large as possible.

The other one is that by expressing $n$ into a binary representation. Then, pick the corresponding gold weights in the binary representation of $n$. For example, $n=11$, binary representation is $1011$. So, you should include gold weights  $2^3, 2^1, 2^0$ into your bag. For this approach, you should deal with two cases: $n < 2^{k+1}$ and $n\ge 2^{k+1}$. For $n\ge 2^{k+1}$, you must include all gold bars. If you don’t deal with this case specifically, you will lose 5 points. For correctness of greedy strategy, you should use the property below
$2^i> 2^i - 1 = 2^{i-1} + 2^{i-2} + ...+ 2 +1$  to prove your greedy strategy works. If you don’t do this, you will lose 3~4 points.

3. For both parts, 8/10 for the algorithm and 1 each for correctness and query bound
1. -2 if you do not take care of pairs that never boxed
2. -1 if you do not take care of pairs that never boxed and -1 if you do not verify at the end whether your candidate champion is indeed the undisputed champion.
4. This one had three parts: (If you just got part (c) correct then the points for part (a) and (b) were moved to part (c)).
1. binary: 0 or 1 depending on whether the algorithm was correct or not.
2. 7/9 for the algorithm and 1 each for correctness and run time. -7 if your algorithm runs in time $\Omega(n^2)$ and -4 if your algorithm runs in time $\Omega(n\log{n})$.
3. 4 points for the algorithm and 0.5 each for correctness and run time. -1 if you do not sort $U$ before applying part (b).
Posted by: jiunjiewang | December 13, 2012

HW10 Statistics

HW10 Stats:

Mean: 47.34
Median: 65

Questions 1 and 2 were graded by me(Jiun-Jie) and question 3 was graded by Zihe. Any questions regarding the grading of a question should be directed at the appropriate TA. If there are any questions, you can come to our office hours, recitations, or email us.

Posted by: jiunjiewang | December 13, 2012

HW9 Statistics

HW9 Stats:

Mean: 35.19
Median: 34

Questions 1 and 2 were graded by Zihe and question 3 was graded by me(Jiun-Jie). Any questions regarding the grading of a question should be directed at the appropriate TA. If there are any questions, you can come to our office hours, recitations, or email us.

Posted by: atri | December 12, 2012

Correction on Q1(b) on sample final solution

Thanks a bunch to Jen for pointing it out: I had the wrong solution to 1(b): it should be false. The online version of the solution has been corrected.

Sorry for the goof-up: For those who submitted Q4 on HW 10, change you score accordingly!

Posted by: atri | December 12, 2012

Final exam review session

Thanks to those who turned up for the review session. In particular, thanks a ton to Daniel for taking fabulous notes and agreeing to share them.

You might also find it useful to look at my final exam blog post.

Good luck on the exam and remember: do not panic!

Posted by: atri | December 9, 2012

Solutions to Sample final

Solutions to the sample final questions have been posted. I would recommend not peeking at the solutions till after you have made an effort to solve the sample final questions.

You might notice that the answers are somewhat terse. I wanted to present “model” solutions, which would fetch you full points in the actual grading. Hope this helps!