What Are Some Computer Tricks That a Cs Student Must Know?

What are some computer tricks that a CS student must know?

If you see the types of questions that CS or SE graduates might encounter in interviews, you will notice that often many of them are some sort of brain teasers. These are coming more or less in two types. Those that require some exact answer and require a very basic skill, like understanding of probability or common sense. and Those that cannot really be solved exactly and their goal is to simply see how you deal with a very hard problem that you most certainly have no preconceived idea as to how it should be approached. Let's see some examples to make the above situations as clear as possible. A Russian gangster kidnaps you. He puts two bullets in consecutive order in an empty six-round revolver, spins it, points it at your head and shoots. *click* You’re still alive. He then asks you, “do you want me to spin it again and fire or pull the trigger again right away?” For each option, what is the probability that you’ll be shot? This one even makes it quite easy for you by telling you that the basic skill t are testing is trivial probability stuff. Two bullets in consecutive order out of 6 possible
 trivial combinatorics. So this is very straightforward. I would hire you immediately even if you were to get it wrong due to some arithmetic error IF you were to go to the whiteboard and write down stuff like this. ^^**** *^^*** **^^** etc Once you do that, it is VERY easy to decide what is the case. Here is another. You’re about to get on a plane to Seattle. You want to know if it’s raining. You call 3 random friends who live there and ask each if it’s raining. Each friend has a 2/3 chance of telling you the truth and a 1/3 chance of messing with you by lying. All 3 friends tell you that “Yes” it is raining. What is the probability that it’s actually raining in Seattle? This is also one about probability but this time t want to check whether you can calculate a probability that something is happening by calculating what is the probability that it is NOT happening because it is easier. These are very easy questions and useful too in judging someone’s basic skill set. There are though these other questions that are even more important because presumably, everyone would be able to answer the ones above, but the ones below demonstrate who is really a problem solver. These usually are very unusual and could catch you completely off guard if you do not have a smartypants personality. Here, by “smartypants personality” I mean, you like these things, you enjoy such questions
 not that you are smart. You may be very very smart but not enjoying these questions. Some of those may have an actual solution and some of them might not. Let’s see some examples. You go south for 1 mile, then west for another mile, then north for a mile, and you end up at the same point. You freak out a bit, and you go south again for a mile, then east for a mile and then north for a mile, and you end up at the same point again! Where are you? Now this one is one of those questions that have a definite solution. These questions are pretty much Colombus Egg questions. i.e. once you see their solution t seem obvious and trivial. Well, t are not. What you need to do with such questions is to immediately eliminate the impossible
 So if you go to the whiteboard and you draw the path described, you see that this cannot be done. It is impossible
. on a 2D surface. So since the question talks about north east south and miles, we are talking about earth, which is a sphere. So from there, it is easy to see that on earth this can indeed happen if you are on the north pole. Here is another that checks your inventiveness. You’re in a room with three light switches, each of which controls one of three light bulbs in the next room. You need to determine which switch controls which bulb. All lights are off to begin with, and you can’t see into one room from the other. You can inspect the other room only once. How can you find out which switches are connected to which bulbs? It also has an exact solution, i.e. you CAN indeed answer it, and it is also a Colombus Egg question. What t want to see here is whether you can be organized. For example, start by saying LR is the lights room, and SR is the switches room. L1, L2, L3 are the names of each light, and S1, S2, S3 are the names of the 3 switches. Now once you have done that, it is very easy to reason in a systematic manner. Very easy to reason does not mean very easy to solve, however you are not totally swamped at this moment. The trick here is to realize that if a bulb is on, it radiates, 2 things. light and
 heat. I will let you take it from there. You see the above situation is very typical to encounter in problem-solving. Say, you are about to use a data structure for its main property, and you can also use one of its indirect consequences. A hack if you will! Finally, there are the most interesting questions of all. These t do not have an accurate answer and so t could be the easiest and also most difficult to answer. For example, something like. How many tennis balls can you fit inside a school bus? How much would you charge a city for cleaning all the city’s building windows? How many piano tuners are in Chicago? Stuff like that. When t ask you these questions, t want to see if you panic and how do you approach a seemingly impossible task. You see, as a problem solver, these are the types of problems you will most frequently encounter. Problems that you do not even know where to start. Something like, your team is tasked with developing a solution for the identification of blurry photographs. I mean, if you were tasked with that you should feel like Bender here. But then again THESE are the interesting problems. So for example, if you answer the “how much would you charge a city for
” question, with “$10 per window” you did not answer the question exactly, but you did provide an accurate answer. You found a way to circumvent the unknown quantity there which shows that you are a smartypants, and more importantly that you did not freeze! But you do not have to answer exactly as I said, all t want to see is that you can reason your way in a convincing way. T won't know the answer either. These are not questions that t expect you to answer, but rather questions that will show to them your skills at work. The amazing thing about these questions is that even if I were to give you my own answers right now, it would matter little if at all, in how much you would be prepared. You cannot prepare for these things. T do not fit neatly in some category that you can train yourself to recognize and answer appropriately. T really do check your reaction on something that you cannot possibly have been prepared. So these are the skills that people should and do, look for in candidates. Basic reasoning skills, a basic understanding of fundamentals, inventiveness, ability to compartmentalize, ability to be systematic, and the ability to not become terrified if presented with the stuff that problem solvers ARE presented with in real life.