The Student Room Group

Computer Science - Cambridge interview

Hey!

I just wanted to know if there were any computer scientists among us here; how did you interviews go? What were you asked, and at what college?

I applied at Selwyn, got three interviews+TSA exam on same day. TSA went OK, nothing more nothing less, and as I'm sure you're aware its difficult to determine whether or not your answer is correct. However I don't think it went too bad either.

1st interview: this was a general one, where we discussed my hobbies/my school/stuff on my statement. It went on to us talking about holidays. Overall it went really well :smile: .

Second one was a technical one (for the NatSci part of the course),where the guy said "let's get to work" and within a few seconds he threw at me a mechanics M2 style question. To be honest it was a dead-easy question, though I made quite a few dumb mistakes as I worked my way through. He then gave me another similar question which had the same level of difficulty:almost none at all. And that was it!

Third interview: technical one (for the CompSci part): having no knowledge of computing (minimal), the guy put me on the spot and asked me a question a) I didn't understand half the vocabulary b) was 2 mins long,uninterrupted. I was so confused. I knew that at Cambridge they tended to ask you questions you were unfamiliar with, and they don't expect you to have a firm;they just wanna see how you would go about solving it. But when the time came, I had totally forgotten that, and completely blanked. He had to repeat the question 5 times before I "understood" it. I suggested an intelligent answer, to which he replied "it's good,but not what I'm looking for... ok shall we move on?" then he asked another question, again where I barely understood. Overall, it went terrible!

To be honest I doubt I got in, but it was a good practice none-the-less.

Have applied @ IC, Bristol, Edi, Warwick, York have offers from all five.

What's your story?
I just got back from interviews and had several in a row as I'm from overseas and wanted to get them done in one fell swoop.

I applied at Wolfson for CompSci, and had my interview there first. I have to say it was the most stressful of all of them, the only one I dressed for, and probably the technically most challenging.

First of all, I dressed in a very nice black jacket, tie, good wood slacks, and I walked in and there was a kind-faced old man who was the admissions tutor, he was wearing a button up. The two CS people both looked like they used the floor to store their clean laundry and wore very wrinkled shirts (one of the shirts was silk too) and looked out of place even in those. The more senior of the two had wild hair akin to Einstein. So needless to say I felt very much the odd one out, and learned from the lesson in my following interviews and dressed more casually.

The general questions are typical of what I expected, what do you do at your job, where are you interests, why didn't you go to college right away (since I didn't) etc.

Then came technical questions. I really screwed up the first one. It was pretty simple trignometric expression and I had forgotten most of trig the moment they asked me despite studying it. So I feigned and said I hadn't done trig in 5 years, and they asked me to try anyway, and to try graphing it to solve it. I screwed up the graph at first and they had to correct me on it several times. Eventually we got to the answer... 1.

So this was the low point in the interview, and I felt like I couldn't do much worse. Then I got questions on how to simplify a low level algorithm, and did well, at one point he asked me to think about how I could further optimise it by thinking about the stack, and I said I wasn't familiar with stacks or optimisation because I typically worked in higher level programming languages. He then turned this into a question about why higher level programming languages were better, which I also answered well.

The next question was about register machines. They wanted me to do several things with register machines, which is similar to a turing machine but more useful. Fortunately I have seen these machines before. I can imagine this question being very very very difficult if you haven't seen the concept of such limited machines. The culiminating question was "how do you make a register machine that multiplies two numbers together?", which is quite difficult. We walked all the way through it and I only got stuck once at the very end where they asked me to do something rather difficult with the machine, and it didn't seem to matter much to them that they basically told me how to do that.

There were several points where they told me that I didn't have to be so clever about things and that a simple answer was equally good, because at certain times I would just stare trying to think of a better solution than the first one. I'm not sure if this is good or not because often it lead to long periods of silence.

All in all, they were quite kind after the first one, they're only human and it was pretty easy to see their body language and reactions to my answers. When I went off in a tangent, it was bad, when I got the right answer, it was good. They weren't stoic stone faced prosecutors.

The TSA was, well, the TSA. It's a goofy IQ test that seems very biased toward english speaking debaters, not computer scientists. I would give it to nerdy lawyers instead. If I "failed" it I wouldn't shed a tear, and if that was the reason I didn't get in, quite honestly it's their loss overall for relying on such a stupid test to judge students. That said I think I did well enough on it that it won't be a detractor to me, like I finished it with a minute or so to go.

All in all, I terribly screwed up the first question, which was the only basic maths question in the interview. They specifically told me later that I would be expected to be successful in NatSci as NatSci was at least 25% of the course. I said that I felt I just needed to brush up on it and I would be taking courses in the spring at a school in the US to get back up to speed.

I think I did well or well enough on all the other questions, and at the very least I did the best I could. If I were to gamble on it, and I am a gambling man, I would say I have a 65% chance of getting in.

I applied at ICL, Edinburgh, Warwick, York, and Manchester. Thus far I have an unconditional offer from Edinburgh, and the other interviews were with York and ICL. ICL told me I would be getting my offer in 10 days in no uncertain terms, York I suspect will do the same. I haven't heard anything from Warwick or Manchester but frankly don't care as I'm going to take either ICL or Cambridge.

If you want more gory details you can read my blog: http://www.dubious.biz/blog/
Reply 2
Telephone interview here. Homerton College.

First, I was asked general questions like "Why Cambridge?" and "Tell me a little about yourself." The following question, IIRC, was "Describe a sort algorithm to me." That was very easy. Then, I was asked how many comparisons are necessary in a sort algorithm. I didn't know that, but I said that it could be n-1 + n-2 + n-3... so the sum of all consecutive integers until n-1, which has it's own formula which I knew from math class. I was told that was a good estimate, but I have no idea if it really were (can anyone clarify please?). I was explained several aspects of the course, such as the 25% NatSci thing, and I was told I wold take Physics (which is my only NatSci IB subject). I was asked some physics questions, like if I had covered thermodynamics and if I had done any lab work. I answered yes to both of them. So then I was asked to describe the most recent experiment I did. I recalled one experiment in which we investigaded what factors affected the period of a pendulum, and also tried to come up with a mathematical expression for the period. I was then asked if the period depended on the mass. I answered "no, I don't think it does", and then I was asked if I understood why. My mind went blank there, so I answered I didn't really know, and then I was told it was okay and I was explained the answer.

Before the physics question, I was asked what was my favorite subject, and I answered maths. I was told that unfortunately we were not going to be able to make problems over the phone. I was dissapointed because I was pretty confident with math problems. I was then asked if I knew how to do some operations with matrices, which I do know. I was also asked if we had covered any set theory, which I answered no, but now that I think abaout it, I think I should've said that we covered Venn diagrams and basic operations like union, intersection, and complement. I was also asked if I knew how a chip worked. I really didn't, and I made something out which was totally stupid ("it probably has to do with 0's and 1's", I answered). I was asked another question about the Internet, which I couldn't understand completely because my phone started making some strange noise, I asked for repetition, but I still didn't get it, so I answered "like search engines, for example?" and I think that had something to do with the question, so I was then asked if I knew how one works. I answered that HTML code has some tags which contain certain keywords, and that the search engine looks them up. I totally missed the point about "indexing" and links (one site leads to other similar sites), although I could have really answered that if I wasn't under pressure. I was also asked if I knew about how many sites an engine searches, and I answered they were billions (which I remembered seeing at the bottom of Google), which I'm pretty sure was correct. I was also asked a little about my written work, which was my IB Dossier for a program I had written in Pascal for my Computer Science course. I was mainly asked about how I tested it. I was finally asked about what I liked to do outside class.

I really have no idea of how I did. At some points I couldn't understand correctly because of the phone, and so my answers were vague, and that was worsened by the fact that English is not my native language.

BTW, I did not took the TSA (I was never asked anything about it). Do you guys think that is bad? I've started to worry about it... perhaps they did not ask for me to take it because I had no chance of admission.
Reply 3
hey,

about the TSA I don't think you should worry: not all colleges require it. Also, to avoid cheating etc we had to do it on the computers of the computer room of the college. I have a friend that applied for engineering at St John's, where he too was asked to do the TSA in the computer room. It was quite funny 'cos whenever you right clicked by accident a pop-up came up "You have performed an illegal operation" + there was a supervisor in the room, to make sure you don't fiddle with the computer. From what you've said, I don't think you should worry: your interview was on the phone, I can't really see how they would have asked you to sit the TSA (I trully doubt they would send it to you over the internet). Secondly, you sit the TSA during your interview, and considering your interview was like 10 days ago, I really doubt they'd NOW ask you to sit it, despite the fact that all interviews for both Oxford and Cambridge are officially over. They've probably already made their minds up. Oxford are sending off their replies as we speak, whereas Cambridge always wait for roughly the 30/31/1st to send your reply (in my case "we regret to inform you that you were unsuccessful" :tongue: I hope not anyway!)

If you didnt do the TSA, that means they didnt want you to (being abroad?)/they don't offer it. Its not because you "weren't good enough". Chill out!

I agree with killermonkeys, the TSA is the most random test to do. I mean its a good one, that actually does test you level of understanding, but surely you need those skills for literary subjects too. I mean, why don't they offer the STEP paper to English Litterature student??!

good luck to all of you!
Reply 4
rolemodel
hey,

about the TSA I don't think you should worry: not all colleges require it. Also, to avoid cheating etc we had to do it on the computers of the computer room of the college. I have a friend that applied for engineering at St John's, where he too was asked to do the TSA in the computer room. It was quite funny 'cos whenever you right clicked by accident a pop-up came up "You have performed an illegal operation" + there was a supervisor in the room, to make sure you don't fiddle with the computer. From what you've said, I don't think you should worry: your interview was on the phone, I can't really see how they would have asked you to sit the TSA (I trully doubt they would send it to you over the internet). Secondly, you sit the TSA during your interview, and considering your interview was like 10 days ago, I really doubt they'd NOW ask you to sit it, despite the fact that all interviews for both Oxford and Cambridge are officially over. They've probably already made their minds up. Oxford are sending off their replies as we speak, whereas Cambridge always wait for roughly the 30/31/1st to send your reply (in my case "we regret to inform you that you were unsuccessful" :tongue: I hope not anyway!)

If you didnt do the TSA, that means they didnt want you to (being abroad?)/they don't offer it. Its not because you "weren't good enough". Chill out!

I agree with killermonkeys, the TSA is the most random test to do. I mean its a good one, that actually does test you level of understanding, but surely you need those skills for literary subjects too. I mean, why don't they offer the STEP paper to English Litterature student??!

good luck to all of you!


All right, thanks!
To answer the sort algorithm question, it depends on the particular algorithm, it has to do with "Big O" notation. The best algorithm is called a "quick sort" ironically and it's O(n log n) (where n is the number of elements in the set), but other, easier to understand sorts are O(n^2). So the very best answer would have probably involved O(n log n) for a quick sort and then you explain the quick sort. However, I don't know how a quick sort works and I only know it exists because I've been studying discrete maths.

They ask questions like that to gauge how much you know about their version of computer science, and as you know you don't "have" to have ever touched a computer to get into cambridge.


Rudess
Telephone interview here. Homerton College.

First, I was asked general questions like "Why Cambridge?" and "Tell me a little about yourself." The following question, IIRC, was "Describe a sort algorithm to me." That was very easy. Then, I was asked how many comparisons are necessary in a sort algorithm. I didn't know that, but I said that it could be n-1 + n-2 + n-3... so the sum of all consecutive integers until n-1, which has it's own formula which I knew from math class. I was told that was a good estimate, but I have no idea if it really were (can anyone clarify please?). I was explained several aspects of the course, such as the 25% NatSci thing, and I was told I wold take Physics (which is my only NatSci IB subject). I was asked some physics questions, like if I had covered thermodynamics and if I had done any lab work. I answered yes to both of them. So then I was asked to describe the most recent experiment I did. I recalled one experiment in which we investigaded what factors affected the period of a pendulum, and also tried to come up with a mathematical expression for the period. I was then asked if the period depended on the mass. I answered "no, I don't think it does", and then I was asked if I understood why. My mind went blank there, so I answered I didn't really know, and then I was told it was okay and I was explained the answer.

Before the physics question, I was asked what was my favorite subject, and I answered maths. I was told that unfortunately we were not going to be able to make problems over the phone. I was dissapointed because I was pretty confident with math problems. I was then asked if I knew how to do some operations with matrices, which I do know. I was also asked if we had covered any set theory, which I answered no, but now that I think abaout it, I think I should've said that we covered Venn diagrams and basic operations like union, intersection, and complement. I was also asked if I knew how a chip worked. I really didn't, and I made something out which was totally stupid ("it probably has to do with 0's and 1's", I answered). I was asked another question about the Internet, which I couldn't understand completely because my phone started making some strange noise, I asked for repetition, but I still didn't get it, so I answered "like search engines, for example?" and I think that had something to do with the question, so I was then asked if I knew how one works. I answered that HTML code has some tags which contain certain keywords, and that the search engine looks them up. I totally missed the point about "indexing" and links (one site leads to other similar sites), although I could have really answered that if I wasn't under pressure. I was also asked if I knew about how many sites an engine searches, and I answered they were billions (which I remembered seeing at the bottom of Google), which I'm pretty sure was correct. I was also asked a little about my written work, which was my IB Dossier for a program I had written in Pascal for my Computer Science course. I was mainly asked about how I tested it. I was finally asked about what I liked to do outside class.

I really have no idea of how I did. At some points I couldn't understand correctly because of the phone, and so my answers were vague, and that was worsened by the fact that English is not my native language.

BTW, I did not took the TSA (I was never asked anything about it). Do you guys think that is bad? I've started to worry about it... perhaps they did not ask for me to take it because I had no chance of admission.
Reply 6
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