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 Virtudyne
Admin
In which case using the word 'pass' is highly misleading and confusing. According to your understanding of the rules, the players receive their hats, take a moment to look at each other and then respond by what they see. It would be much better phrased as Once they have had a chance to look at the other hats, the players must simultaneously guess the color of their own hats or remain silent.
It would be equally appropriate for the interviewer to disregard me for not understanding as it would be for me to disregard this boss for being unable to communicate clearly.
Admin
hat question... if you're allowed to move around... anyone that sees the same color hats on the other two moves to the center, if they see different colored hats they move to the out side. anyone in the middle knows his hat is opposite of the other two, if everyone is in the middle they're all the same.
Admin
Because the diameter of a circle is consistent, and a round manhole cover won't fall through the hole.
Admin
I was in a roomful of Accenture folks today ... everyone acted and thought the same way (and dressed  seriously does accenture have an outlet store or something?). I've observed the same about Microsoft ... everyone I know in the place that handles a technical job acts and thinks alike. And yet both of them can't seem to get anything done ... or at least get it down correctly, on time, or on budget.
Teams need to be diverse and good managers/hr personnel should look for people that have skills that balance other's skills on the team.
These types of interviews have a habit of excluding ranges of people that would greatly benefit the organization but because they don't fit into some arbitrary mold they don't get hired.
Admin
BBQ the chicken, blame it on the fox, and claim crop insurance.
it might not get you a programming job, but if you're going for sales or marketing....
Admin
have everyone but the person that sees 2 colors pass and guess opposite of the 2 colors.
Admin
I interviewed at Microsoft several years ago and got asked the following brain teaser: Given a rectangular piece of sheet metal with a rectangular hole in it, where the hole is not in the center of the sheet metal, how can you make one straightline cut that results in two pieces of sheet metal with equal surface area? My answer: "Well since it's made of metal, melt it, pour it into a level, rectangular container, let it cool off, and chop it in half down the middle." The interviewer laughed and gave me credit for a creative but incorrect answer. The correct answer was to cut a straight line that travels through the center of the hole and the center of the sheet metal. I still like my answer better...
Admin
These lameass riddles are a (weak) proxy for IQ. Ideally, the employer would sit the applicant down with a a standard IQ test, and also a test of general programming knowlege. Or maybe just the IQ test. But for various reasons (read: lawyers), they aren't willing to do this.
Admin
NO COMMUNICATION means NO COMMUNICATION guys...
Anyway, here's a simulation that proves you can win 75% of the time in the red/blue hat problem:
http://polesocking.com/hats.php
Admin
Here's what you said:
How is that different from saying you would disqualify someone simply because you are too unoriginal to come up with a ridiculous brain teaser that the candidate has [not] already heard? (I realize I forgot a word in the original statement.)Admin
To anyone so hung up on the word "simultaneous", consider a logically equivalent contest, where "Three players enter a room and a red or blue hat is placed on each person's head. The color of each hat is determined by a coin toss, with the outcome of one coin toss having no effect on the others. Each person can see the other players' hats but not his own." is replaced with "Three players are separated from each other and given hats, the colour of which is determined by an unbiased source of random bits out of a choice of either blue or red. Each of the players are told the colour of the other two players' hats, but not their own. Each player then chooses one of blue / red / pass, indicating their guess of their own hat's colour."
Admin
Exactly one person makes a random guess. That makes a 50% chance for winning the prize. Who makes the guess is decided beforehand.
"How would you determine the weight of a Boeing 747?"
Easy, by weighing it up with Xboxes 360 and multiplying with 8.5lbs.
Alternatively, I'd throw it in the ocean and measure the increase of global sealevels.
No, seriously, I would look it up in Wikipedia, err, I mean Microsoft Encarta, of course.
"Given an opaque box with three light bulbs inside and three switches outside, how would you determine which switch corresponded to which bulb if the box could be opened only once and only after all the switches were permanently set?"
Assuming that all switches are off at first, I would enable two switches (let's call them A and B), wait a few minutes, turn off B and open the box. Now the A bulb is on and hot, the B bulb is off and hot, and the C bulb is off and cool.
Admin
Come to think of, I agree with you. These brainteasers are more like I.Q. tests. I mean, you always emphasis on what you have stumbled upon in your way up to the professional ladder. I would really love to see the other way around, something like 'I didn't know this one, but can you tell me what is the result of multiplying all figures from 0 to 25 ?' Should we fire the inteviewer because it is caught by surprise and allows himself 1 minute till he figures it out?
Admin
Dry dog food or wet? What is its density? What is the volume of dog food consumed in the US annually? Digested or undigested?
Admin
The light bulb problem is easy. Turn on two switches for a minute, then turn off one just before opening the box. The lit bulb obviously goes with the "on" switch. The warm bulb goes with the switch that was just turned off.
To measure the weight of the jet plane, measure the tire pressure in each tire on the ground. Estimate each tire's surface area touching the ground as a rectangle. Multiply each tire's pressure by the surface area and add the weights.
The fastest bridge crossing can be done in 17 minutes with this sequence: 1 & 2 cross, 1 goes back. 5 & 10 cross, 2 goes back. 1 & 2 cross. The total time is 17 minutes.
Admin
Blame Microsoft. It's always Microsoft's fault.
Admin
The 747 weight. Google it.
The box. Trace the wiring.
Crossing the bridge. 1 and 2 cross together. 1 returns and crosses with 5. Either 1 or 2 returns and crosses with 10 after 5 reaches the other side. Total time = 17 minutes.
I would not get the job, because obviously MS was not looking for a Google search.
Admin
If I do give such an interview for whatever value it has, I would certainly give the job to the fan blow idea, it's very clever, albeit a bit cruel.
Admin
The chance of one hat being one color or another is always 50%, regardless of the color of the other hats.
The fact that two hats are red does not change the odds that the third hat is blue.
Misunderstanding of this concept is the reason casinos are profitable.
Admin
I'll bet you a million dollars that I can give you a strategy that will win 75% of the time.
Admin
I got no such questions when I interviewed with Microsoft. Just interesting coding questions mostly relating to algorithms. And yes, I got the job. The company is not quite as evil as people make it out to be.
Oh, and by the way...why are manhole covers round? ;)
Admin
It depends on where you place the importance of the "OR"
"the players must simultaneously guess the color of their own hats or pass"
this could be .. (simultaneously guess colour) OR (pass)
therefore the "PASS" does not need to happen at the same time as the colour guessing ..
I stand by my previous strategy .. tell others to Say Pass , if they can see two different coloured hats , if you hear two passes then your hat is opposite of the others .. if you hear one pass then it is the same as the person who said pass , if you hear none , then they are all the same .
Admin
You really live up to your pseudonym. We don't care if any given person is correct or not. That's not the point of the excercise. We care about a system of either answering or abstaining from answering that yields the highest chance that at least one person will answer correctly, and no people will answer incorrectly. This can be achieved 75% of the time, as has been explained over and over in the comments.
Admin
1 & 2 cross: 2 minutes 1 goes back: 1 minute 1 & 5 cross: 5 minutes 1 goes back: 1 minute 1 & 10 cross: 10 minutes Total: 19 minutes
The correct answer is as follows: 1 & 2 cross: 2 minutes 1 goes back: 1 minute 5 & 10 cross: 10 minutes 2 goes back: 2 minutes 1 & 2 cross: 2 minutes Total: 17 minutes
Admin
Actually I was more hung up on the word "pass", and whether or not each person had to guess a color. If the rules are as you explain, and only one person is required to guess, then the chance of success is indeed 3/4. According to my previous understanding of the rules (all players must guess when one guesses) and the word simultaneous, the chance of success under ANY strategy is 1 in 8.
So if an interviewer wants to determine how an applicant reacts to vaguely worded instructions, ie, do they ask for clarification or plow on and try it by themselves with limited understanding, by all means use this test as worded.
In my interview I was asked to write pseudocode for a relatively simple problem (something like count the number of identical occurrences in an array).
Casinos make money because the odds are always (over the long term) in their favor, not because people do not understand odds.
Admin
You know what? Let's just leave it there. I think you're an arse, you think I'm an arse. I wouldn't want to work for you, you wouldn't want to hire me. Your selection procedures are clearly working for you, so hey  run with them! You'll be saving anyone like me an awful lot of hassle if we can take flight at interview, rather than having to suffer working with you.
Admin
I work at Microsoft and I hire people at Microsoft. You're absolutely wrong on every point you assert. Even the stuff you're half right about, you're still wrong on.
Just thought I'd point that out.
Admin
It seems to me that the statement .9999... == 1 is equivalent to asserting that there is no such thing as an "infinitesimal" real number.
This is not particularly obvious, especially when you consider the fact that in calculus, quantities such as "dx" are supposed to be infinitesimal!
It's quite possible to have alternative algebras in which there are infinitesimal numbers, for one example see: http://en.wikipedia.org/wiki/Hyperreal_number
So I think it is being a little harsh on those people to abuse them for not intuitively accepting our current view of real numbers, which by the way was not formalised until the 19th century  Newton, Euler and all the other greats were unable to provide a rigorous theory of real numbers either.
We (you and I) have worked with real numbers for so long that they are now an intuitive abstraction to us and it's hard to see them from another point of view.
Admin
As far as to why manhole covers are round  I think this is fucking stupid. Yes, yes, so that it won't fall into manhole. Cool. But how about digging a square manhole? Or, in fact, any shape that is not round?
Admin
Complete practicality of the answer? Right there is some horrendous bias and superiority complex. Typical of a programmer who would code to their own needs rather than their customers'; who doesn't bother trying to understand his customers. The two reasons that spring to mind initially on why this idea isn't 'completely practicable' are that visually impaired or blind doesn't mean no sight at all, and you can still tell even without sight when your bike is stationary from simple proprioception.
Right now I'm testing software from a programmer who doesn't understand his clients. He's wasting time on minor shit that the customers don't care about, and the primary function the customers want is "ah, noone really cares about that". Programmers with a superiority complex need to be shown the door.
Admin
Nope... Not right.. However you look at it or however you want to think about it, the chances are 50%. No matter what colour the others are wearing, you will only have a 50% chance of winning, i.e. using your logic if the others are all wearing 'BLUE' then there is 50% chance that all of you will shout out 'RED' or 50% chance only you will shout out 'RED' and win. Without any communication you cannot get a probability of higher than 50%
/an
Admin
In the US, the assumption is that a bicycle will be used on or near a public street used primarily automobile drivers who have, on the whole, a very poor record in the driving safety area. There are very very few cities or even rural areas with designated bike areas. So the solution is not so farfetched.
However, many visually impaired persons will ride a bike to work because they cannot obtain a driver's license.
So the interviewee had some good data, but did not apply it correctly. Probably not a good candidate.
Admin
Question by Yahoo! interviewers: How would you go about finding every single barber in Minnesota?
Apparently incorrect answer: Google it.
Admin
OK: There are 8 possibilities for hat distributions. Here's the strategy: everyone calls 'BLUE.' The only way to lose is if they all have red hats, and the chance of that happening is 1/8, and hence you have a 87.5% chance of winning.
Admin
No, it'a a proof from a fucking definition.
Admin
Somebody stop this madness, I'm begging you.. anyone... please.....
(I actually read every page, that's why... too much time in my hands during lunch...)
Admin
Answering the question, no matter how brilliantly, would not have guaranteed getting the job, but in any case, asking what the point of the question was certainly didn't earn you any points. Why can you still not accept at face value the reason they gave you? The point was to see how you reason things out.
Admin
Assuming that all the quarters look the same, I would drop the quarters on a hard surface and listen to the sound that they make. The quarter that sounds different is the one that is made from a different metal and therefore is going to weigh differently.
Gloves.
This solution has a O(zero) in terms of number of uses of the scale. I doubt anyone is going to find a more efficient solution than this.
The bigger mystery is why I am replying when there are all those posts before me. (To be honest I stopped reading the replies at page 5, so I don’t know if this solution has been suggested yet.)
Admin
How many persons does it take to form a circle? Tree?
Admin
I am taking a simulation class right now with the professor (Ebert) that came up with that puzzle for his Ph.D...lemme tell you, one smart mother f'er
Admin
Damn! You beat me to it :) This is the very solution I've just developed. Our approaches are examples of emergent algorithms. Each player has two simple rules and the desired solution emerges from each player applying them.
Each player can see the hat colour of the other two players.
Rule during play:
if(the hats of the other two players are the same) move to the centre of the room else move to the end of the room
If we enumerate the possible combinations we can see how the algorithm works:
0s are green hats, 1s are red hats C is centre of the room E is the end of the room
000 CCC 001 EEC 010 ECE 011 CEE 100 CEE 101 ECE 110 EEC 111 CCC
In the first case (CCC), those wearing the green hats end up in the centre of the room, in the 2nd case (EEC), the green hat wearers end up at the end of the room. However, where they end up doesn't matter. The important point about this algorithm is that the people wearing the hats are grouped correctly.
Rule once everyone has moved:
if(I am in a group of three) Say the colour of the hats worn by the other two else Say the opposite colour to that worn by the member(s) of the other group
During the game, each player is acting autonomously, they are just performing their rule. Therefore, there is no communication.
The challenge to the reader is:
Admin
Actually, I wouldn't be surprised if the fox ate the grain, since foxes are omnivores. :)
Admin
I got asked by microsoft how I would design an alarm clock for a blind person. I went on and one about putting all kinds of braille on it and didn't even think of the obvious  make it completely vocal! I was trying to be too practical....
Admin
http://en.wikipedia.org/wiki/Communication
Admin
Very nicely done, I asked all those (except for the digestion one). The response I got to all of them was more or less "I am not sure, what do you think is a good answer?"
Admin
Very nicely done, I asked all those (except for the digestion one). The response I got to all of them was more or less "I am not sure, what do you think is a good answer?"
Admin
Admin
Three players enter a room and a red or blue hat is placed on each person's head. The color of each hat is determined by a coin toss, with the outcome of one coin toss having no effect on the others. Each person can see the other players' hats but not his own.
No communication of any sort is allowed, except for an initial strategy session before the game begins. Once they have had a chance to look at the other hats, the players must simultaneously guess the color of their own hats or pass. The group shares a hypothetical $3 million prize if at least one player guesses correctly and no players guess incorrectly.
What strategy would you use?
the player should settle with one of the players that each of them says the different color and split the money after the game.So you have 100% chance to win the half of the money.If the interview is for Microsoft ,than you can say that you will fuck up you fellow player after the game and took all the money.
Admin
That doesn't even make any sense. Does anyone actually read the problem? Anyone?
I'm beginning to think at least half of the 50%/stealthcommunicate/rulemisunderstanding answers on this thread are trolls trying to antagonize the rational folk.
Admin
Yeah, you are right. Moving before the players announce their guess is a form of communication. Shame!
Even though each player isn't communicating in terms of speech, a covert channel has been opened. There is no scope for anything in between each player looking at the other hats and then announcing their guess.