jeffy124's Journal: Getting Hired at MS

I found this interesting. A friend of a friend had a job interview with Microsoft. Apparently, they're interested in how your brain solves problems. During the interview, the person was treated to the following problem:

There are four prisoners on death row. The warden lines them up in a single-file line, and places a wall behind the first person. He then takes two black hats and two white hats, and places them on each prisoner. The first has black, second white, third black, and fourth white. The prisoners do not know what hat they have, but can see the hats in front of them, but cannot see past the wall.

The deal is that the warden will wait until someone says "I have a __ hat." If he's correct, all four get off and can go home. Otherwise, all four immediately proceed to the chair.

All four walk without lucky guessing. How?

Now a realistic question: How many job interviews have you been on have asked stuff like this?

That kind of problem....

[Cliff]

It's unusual to see it given in an interview, but assuming a few things it's an easy one to solve.

Quite simply, if any one prisoner knows the colors of the other three, then it becomes obvious what the guy behind the wall must be wearing. Once all 4 colors are known, it then becomes a simple exercise in logic what color hat everyone has to be wearing.

I think interviews that ask these kinds of questions are better indicators of what a person knows and how a person thinks as opposed to answering loads of questions that dance around the issue, or questions that imply that a person know specifics about a job based on a title, like "Do you know anything about Process Management." -- which I was asked in a recent interview. Both questions have their place, though.

Truth be told, I prefer interviews that do both.

hm, i've never been asked this type of question..

[Make]

2 months ago i had been looking for a new job, had several interviews. but in all interviews of my life, i have never been asked something which would reveal my *real* technical skills! *sigh*

"{do you know| can you do} {XML| databases| UML| this and that| foobar}"

but what the fsck does this tell about my skills as software engineer? in my opinion, it's not about knowing some interface or language or API, it's about solving problems.

seems like m$ would be a nice employer for me. why not? (if i would ever enter the USA in my life, but that's a very different story)

Re:hm, i've never been asked this type of question

[arb]

but what the fsck does this tell about my skills as software engineer? in my opinion, it's not about knowing some interface or language or API, it's about solving problems.

Because one of your primary your skills as a software engineer should be an ability to solve problems. Knowing a particular API is not such a big deal, but knowing how to find information about an API you are unfamiliar with is. As is knowing how to solve the coding problems you are presented with as part of your work. So long as you can prove to me that you can write solid code in a couple of different languages, that you know where to find answers to problems that stump you, and that you know how to think, you are a prime candidate for a job. I have interviewed many people for different positions, and the ones who are all about their technical brilliance tend to be the wrong people for the job. So long as they are well within the confines of their particular (usually narrow) area of expertise, they are great, but toss them a different problem and they struggle to find a solution.

If you can't think your way through a problem, you aren't right for the job.

Asking someone - do you know XML is pointless. Of course they are going to say "yes". Asking them how would you solve a problem (code related or not), and getting them to talk through their thought processes reveals a lot about their problem-solving skills. Of course, you should be asking general logic questions and technical related questions in an interview. If the candidate ends up giving a wrong answer, that is not necessarily a bad thing, so long as they explain how they came up with the answer.

So what relevance does this have to software engineering? In my opinion, software engineering is not about knowing some interface or language or API, it's about solving problems.

mastermind game

[Raiford]

... sounds like a simple derivative the game mastermind played cooperatively with just two colors.

I have never had an interview with that kind of question. The questions that I remember were more concrete and applications oriented.

I did ask a potential faculty candidate once the question: "Why are manhole covers round ?". The awnsers that you get seem to tell a lot about the person. For example:

Because the manhole is round. (This is a person that looks for the obvious).

Because if they were square you would have to rotate them to match the hole. Round covers are easier to place over the hole. (This person looks for practical aspects).

Because a circular footprint will provide a maximum area with minimum material usage. (The guy was trying to indicate that area is wasted in the corners along a diagonal if the manhole was square. A weak argument but indicates the person strives to be analytical.)

I suggest trying this question if you have the opportunity to interview someone whether it be a potential employee or a potential girlfriend. The results should prove interesting.

Re:mastermind game

[arb]

"Why are manhole covers round ?"

Because round man-hole covers won't fall into the hole if placed incorrectly... Square, rectangular, oval, or any other shape covers can fit into the hole if oriented in a particular way. Round covers can't...

Microsoft Interviewing is like that

[Safety Cap]

Having worked with ex-'Softies and swapped stories, it appears that their interviewing process includes some challenging math/logic/puzzle problems and at least one impossible problem (ex: How many orthodontists are there in New York City?).

The "goal" of all of these is to "determine how the candidate thinks, not what he knows."

Funny

[baldass_newbie]

My friend interviewed with MS, and they flew him out to Seattle (from Jersey.)
He said it was EXACTLY like the Simpsons episode You Only Move Twice [snpp.com] where Homer takes the job with Scorpio.

Wrong.

[gmhowell]

There was guessing involved. How?

First person can't see anyone. Any answer is a guess.

Second person can't see anyone. Any answer is a guess.

Third person can only see one hat. The other three, including his own, is a guess.

Fourth person can only see two hats. The other two, including his own, is a guess.

There are some unclear possibilities and questions that would clear this up.

Can they see the hat of the first person, even if they can't see the person? Do they know how many hats there are of each color?

Finally, here's a cheat: "I have a [skull cap, fedora, hunting cap, bowler,] on."

Pls. Post answer in journal or something, as I'd hate to miss it.

Re:Wrong.

[arb]

If the last person saw two hats of the same colour, he would know he is wearing the opposite colour, so he could answer. The second last person, not hearing the last person answering immediately, knows that his hat is the opposite colour to the person in front of him, therefore he can call out the colour of his hat.

Re:Wrong.

[gmhowell]

Easiest thing to do is move discussion to the answer JE (where I just posted). To sum it up: the third person guessed. He guessed correctly, and guessed based on mostly correct information, but it was still a guess.