• s (unregistered) in reply to Andrew
Andrew:
Grandpa said that: - _everyone_ had to guess right --at least one :and: --all // a bad WTF of if(x>1 && x==3){} to win.

WTF?

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.

Inability of converting a set of spoken instructons into a set of logical conditions is a disqualifying failure in a programmer's interview.

Meaning one person guessing minimizes the chance of failure. If one person guesses, the chance is 50%.

Furthermore picking the person according to the "tell color different to the one on two others' heads, or shut up if they differ" would improve the chances to 3/4:

8 equiprobable cases: rrr - rrb + rbr + rbb + brr + brb + bbr + bbb - only rrr and bbb cause all to shout out wrong answers.

• (cs) in reply to gwenhwyfaer

Eeeep! I repent! I repent!

I can only offer the following as an excuse:

The solution I quoted seemed to be using 9 coins ({0} - {8}) in some places, so I didn't give it the consideration it deserved and just plowed ahead with my response.

As for the rest of your bullshit: you're being a dick. :-)

I made a mistake by not making sure I fully understood a solution before I said that I thought it was incorrect. I then posted the reason that I thought the solution was incorrect (I wasn't trying to present my own, different solution). Obviously, the "flaw" I pointed out in the given solution (that some scenarios will require 4 comparisons) doesn't exist because I misunderstood the solution in the first place. That's my own damn fault; I was lazy, and I apologize for it. But that's it. I'm not anti-intellectual, I'm not falsely humble, and I'm not responsible for creationism being taught in public schools, global warming, or even down syndrome. Geez...

Addendum (2007-05-16 15:27): Meant to quote this the first time:

gwenhwyfaer:
UncleMidriff:
Undefined Reference:
Nope, Min 2, Max 3.

{...snip completely documented method...}

I get Min=2, Max=4, Avg=3.25 {...snip a big pile of waffle...} If I am wrong, please call me on it.
That might have been a reasonable thing to say if you were pointing out an error in the post you were replying to. But you didn't do that. You contradicted him for no good reason, waffled a lot about situations without ever actually enumerating the possibilities, completely failed to show (or even attempt to show) any error in the parent's methodology, and presented your suboptimal, inadequately documented, possibly incorrect solution as somehow superseding the complete, fully-documented, optimal solution you totally ignored.

It's this mindset which will ensure that creationism ends up being taught in science classes, despite not being science, because "it's a valid alternative". It's anti-intellectualism coated with a veneer of faux humility and a disingenuous claim to egalitarianism. And it really shouldn't be allowed to show its face in public.

So read and understand - when your solution is less optimal than solution X, you have shown that you are aware of X, and you have not demonstrated a flaw in X, you should be learning from X, not trying to present your solution as somehow "just as good really", or "worth airing anyway", and ESPECIALLY not a successor to X! Share your thoughts, sure - but quoting someone else's solution before presenting your own implies a criticism of that solution, so you'd damn well better actually make such a criticism.

• Someone (unregistered) in reply to Andrew
Andrew:

Grandpa said that everyone had to guess right (at least one and all) to win.

No. Read it again. At least one has to guess correctly, and no one may guess incorrectly. Remember that they can choose not to guess at all.

• s (unregistered) in reply to Michael
Michael:
You were only asked to locate the odd coin, not figure out if it was heavier or lighter.

Yep, but in the "heavy coin" case you pick the heavier side for further analysis, reducing your deduction to 2 measurements. In case of "different coin" you don't know whether the left scale is heavier than it should be, or the right scale is lighter, so when you determine all coins on the heavier scale are equal weight, it means your coin is lighter and you need to test the coins from the other scale. 5 measurements max.

• Undefined Reference (unregistered) in reply to UncleMidriff

I was not the one who criticized you. But the solution was mine.

I did indeed solve the puzzle for 9 coins instead of 8. Though the best solution was the method using fixed weighings. The solution I posted has one case in which it requires fewer weighings.

• (cs) in reply to Undefined Reference
Undefined Reference:
I was not the one who criticized you. But the solution was mine.

Yeah, I know. Apparently, I can't work the quote button either. Sorry for the confusion.

• Anonymous (unregistered)

For what it's worth, I've been through 4 interview loops at MS and only once did I encounter the brain teaser deal, which was about 7 years ago. I would say that it is NOT standard practice, and perhaps the idea to use them came about as a way to understand a person's problem soloving ability without violating their NDA. Addtionally, I would guess in the programming space, you would be more likely to encounter an actual generic programming problem to solve vs. a silly brainteaser problem.

• (cs) in reply to YourMoFoFriend
YourMoFoFriend:
me:
Or his sense of self-preservation?
How's that? By showing that he is so full of himself that he'd rather blow an opportunity than give a riddle at least a try?
No. The propensity to evaluate performance through inappropriate criteria is a pretty good indicator of WTFery.
And you know that interviewer is an arsehole how?
He just pulled an arsehole's trick on me.
So far he just put you in an unexpected situation
For one thing, it's hardly an unexpected situation any more. For another, you're begging the question.
and you showed your total inability to handle it, not to mention your lack of respect to the interviewer.
The interviewer just showed me a lack of respect. I think I'm entitled to return it. Remember, I'm interviewing his company too; I have the right to refuse any job offered. What you seem to be saying is that I should consider myself lucky to be so abased, which is an attitude I find contemptible.
Would you want to hire the person who wished they had?
No way. These are the same arseholes that think everything in a company revolves around them.
I have a sense you didn't quite understand what I said there.
WRONG. Business revolves around business, sales, marketing and sometimes... well customers and their needs.
But before any of that - business revolves around trust. Integrity is a necessary precondition of trust. You seem to regard it as optional - that way lies the pyramid scheme and the pump'n'dump.
And more often than not customers needs are unexpected, stupid and yet have to be done the way customers want them to be done.
Yes, they are, but last time I checked, customers won't insist that they want a version of Doom inside their production line controller, or something equally asinine - and you always have the option of telling the customer that something is impossible, or impractical, or however.

But as I say, you're begging the question. On what basis do you believe that the ability to pretend to solve silly brainteasers actually does lead to flexibility?

Last thing I need in my team is the guy who walks out instead of at least trying to analyze and solve a problem
Then you don't understand why the guy walked out. You think it's because he couldn't be bothered to solve the problem? If you'd bothered to find a real-life example from the business you were supposed to be selling him, rather than pulling up www.stupidarsedpuzzlefortheday.com and reeling off the first one you read, he would not only have stayed in the interview, but given you the very best answer he could come up with. But you didn't; you were lazy, contemptuous and unprofessional, and he won't tolerate you asking more from him than you're prepared to give yourself.

And frankly, your attitude suggests you'd have trouble with the exhibition of a backbone too, which is another big warning sign.

• Charles Bretana (unregistered) in reply to JM

Actually, the simplification you are remembering from high school calculus is only true when mass distribution satisfies spherical symmetry (i.e. is dependant only on the distance from the center and not on latitude or longitude) This assumption is not 100% true for any real body (the earth included)

JM:
Sorry, this comment: Actually, it's perfectly correct, the mass of the Earth *is* concentrated at it's center. While the side of the Earth you're standing on is 1 radii closer to you than the center and therefore attracting stronger, the side directly opposite is 1 radii further away and is attracting weaker.

So if you sum all the attractions from every grain of sand and piece of rock over the entire volume you'll find that it all balances out, and the result is identical to the graviational attraction of a single massive pellet at the center with you suspended in space 1 radii above it.

Physics 101. Comes in handy sometimes.

Was in response to this:

`````` brazzy:

Flo:
- Measure the gravitational constant, find your own mass and the radius of the earth, use Newton's law of universal gravitation. Simple.

Simple and quite wrong, since the Earth's mass is not concentrated in a point and thus not all at the same distance from you.
``````
• (cs) in reply to Grumpy Young Man
Grumpy Young Man:
"For myself, I couldn't understand why I would have to artificially bloat up my working by 200-300% just to meet someone else's standards; and I still don't get arbitrary rules nearly two decades later."

No hire; not a team player.

Thank you. That's the nicest thing anyone's said about me all week.

(I actually find interacting with people painful - largely because 99% of them are fuckwits. Sweetie, you didn't make the top percentile.)

• Rick Deckard (unregistered)

Right on!!! In the end it doesn't count who you are as aperson, or what are your personal complexities... One human being is as good as the other and these tests only accomplish in making the world a worse place..

• tuesday (unregistered)

the boeing 747 one could be solved by using about 10 dollars worth of art supplies and a pressure guage.

a pencil

a few sheets of poster board, or just a large roll of butcher paper.

tire pressure guage for jet tires (im sure there's one)

use the paper to calculate the area that each tire occupies on the ground

multiply by the PSI to get weight supported by each tire

gimme job!

• Mike (unregistered) in reply to Grandpa

If you look and the other 2 hats are matching color you guess the opposite color. If the two hats are different colors you pass.

• unknown (unregistered)

Best interview question ever...I got this after being grilled by 5 people at a company in Hackensack, NJ (you know who you are):

"How much would the water level rise if the average annual consumption of dog food in the US were dumped into the Dead Sea"

What the crap is that?

• Randy (unregistered)

They just stole this from McKinsey and company. They've been asking stupid questions like this for years.

• DR (unregistered) in reply to vt_mruhlin

I actually had that question at a job interview at Microsoft. I gave the optimal answer and was essentially given poor marks for not coming up with others.

You take two sets of three coins from the eight. Weigh them against each other. If they balance then one of the two remaining coins is heavier and you can compare them. If one of the two sets of three is heavier then you can pick two coins at random and compare them. Either one's heavier or the third coin is the odd heavy coin. This results in an answer with two weighings. Dividing by 2 each time requires 3.

• GitReal (unregistered) in reply to Talchas

learning about what others have does NOT tell you anything. All those who think otherwise have not learned probability.

Surely the first rule to approaching answering these riddles is to question whether you are really as clever as you think you are....

• Ken (unregistered)

Actually, I think the "brainteasers" on this thread have shown that they can be relevent to a new hire.

Do you want to hire someone who knowingly and deliberately violates two very important requirements of the specs? (ie: the "three hats" problem, where people are giving "solutions" involving communicating and non-simultaneous responses, or simply ignoring the "one wrong answer means failure" criterion.) "I know the specs said it has to run on Windows and Linux, but I decided to write a Windows-only library instead." "I know the specs said to refuse to unlock the door if any of the biometric compares failed, but I figured that it really only needs one to pass in order to open."

Do you want to hire someone who says "I'm sticking with my first answer, even though it has been proven wrong, over and over"?

Or would you rather have someone who answers "have one person pick a color at random for 50%", but when told there is a 75% solution, is open to suggestions? (And, when told the solution, works it out and says "you're right -- that is better".)

I am one of the interviewers that ask sadistic puzzle questions and I have received a few.

1. Hand the person a mixed up Rubik's cube and tell them that they were hired specifically to figure out this important new technology. If the cannot have it done by the end of the day then they are fired. What do you do?
• try hard fail then get fired (usually a 4.0 gpa student)
• just look it up (normal person)
• Plan to write a program to solve it (big liar)
1. You have a cube 10x10x10 made of smaller cubes 1x1x1, if yo painted the outside of the big cube, how many little cubes would not have paint of them?

-8x8x8

• Nirgaul (unregistered) in reply to Grandpa

The initial strategy session should permit that each player enters the room holding a mirror for the other players to look in so they can see their own hats.

As for the hat question, the initial strategy is as follows, if the persons hat is red, push them to the door, if the hat is blue, push them into the middle of the room, the last person standing would always pass, that way at least 2 will get it right and none would get it wrong

• javascript jan (unregistered) in reply to Ken
Ken:
javascript jan:
... His professional opinion: nobody gives a shit if some idiot drops a manhole cover into a manhole, because they're the one who has to fetch it out. ...
I think the person in the manhole when the cover fell through might have a different opinion.

Well done, you've discovered what an externality is. The man down the hole doesn't make, sell, or buy the mahole covers.

• YourMoFoFriend (unregistered) in reply to gwenhwyfaer
gwenhwyfaer:
No. The propensity to evaluate performance through inappropriate criteria is a pretty good indicator of WTFery.
Thing is, you assume that it is your performance that's being evaluated. Not so. Also, while you're well within your rights to think that the criteria used were "inappropriate", you have no way of knowing if they were or not. And you never will, since you prefer to "walk out" rather then find out.
And you know that interviewer is an arsehole how?
He just pulled an arsehole's trick on me.
Or he just wanted to see if you're a kind of arsehole who can't be bothered with "questions unrelated to the job" :)
The interviewer just showed me a lack of respect. I think I'm entitled to return it.
What? Asking a hypothetical question with no right answer is an insult to you? How else is interviewer supposed to at least have a peek into your behavior in an unorthodox situation? Take your word that you're great under pressure?
Remember, I'm interviewing his company too; I have the right to refuse any job offered. What you seem to be saying is that I should consider myself lucky to be so abased, which is an attitude I find contemptible.
Sure deal. Unfortunately walking out of an interview usually leads to the job NOT being offered in the first place. You can consider yourself lucky, unlucky or a Santa Claus, makes no difference to me, but if your attitude is "WHAT??? Brainteaser??? On an interview??? I'm outa here", more likely then not you will be considered an idiot.
I have a sense you didn't quite understand what I said there.
Perhaps you should've said it clearer :) Either way, I do not want a guy who walks out (nor does he want the job, apparently) and I do not want the guy who wished he walked out.
But before any of that - business revolves around trust.
Agreed. So far you have not showed me, the interviewer, any. All you did was to assume that everyone asking you questions you don't like, is an arsehole.
Yes, they are, but last time I checked, customers won't insist that they want a version of Doom inside their production line controller, or something equally asinine - and you always have the option of telling the customer that something is impossible, or impractical, or however.
I do not know where you "checked", but the principle stays the same: Unexpected, ambiguous situations will arise, and you will have to deal with them. Your attitude towards those situations is what I'm trying to test, not your ability to actually solve some puzzles.
But as I say, you're begging the question. On what basis do you believe that the ability to pretend to solve silly brainteasers actually does lead to flexibility?
If you know the answer to a puzzle and pretend to solve it you're a liar and I don't want you in my team. I also said nothing about "flexibility".
Then you don't understand why the guy walked out. You think it's because he couldn't be bothered to solve the problem? If you'd bothered to find a real-life example from the business you were supposed to be selling him, rather than pulling up www.stupidarsedpuzzlefortheday.com and reeling off the first one you read, he would not only have stayed in the interview, but given you the very best answer he could come up with.
I see, so now you're the one deciding what is and is not appropriate to ask you on an interview (I'm talking about "legal" interview questions here)? Has it ever occurred to you that I MAY ask you a question just to see if you will pretend to solve it knowing the answer already? You have no idea what I'm looking for, yet you make all kinds of assumptions about it. Very professional :)
But you didn't; you were lazy, contemptuous and unprofessional, and he won't tolerate you asking more from him than you're prepared to give yourself.
Assumptions, assumptions, assumptions. That is the problem, you think you're smarter then everybody else and if they don't see how brilliant you are without all them stupid questions they don't deserve your presence in their company. I'm not looking for the best coder (if your tech skills is the only thing I'm interested in I won't bother with puzzles, I'll give you a programming test), I'm looking for a personality, a good fit with the existing team, a person, not just a coder.
And frankly, your attitude suggests you'd have trouble with the exhibition of a backbone too, which is another big warning sign.
Right, saying that it is probably unwise to pass judgment based solely on your misunderstanding of the situation is a sure sign of a "backboneless" man. Bravo.
• name (unregistered) in reply to Grandpa

The strategy is for all three people agree to stand in a circle, each looking at the hat of the person in front of them. If the hat is blue, they take off a shoe. If it is red, they do nothing.

So, the three participants enter the room, and after they line up, each person then looks at the feet of the person behind them, counts to 10, and then simultaneously says their color. Where's my \$3 mill?

• anony coward (unregistered) in reply to Matthew

Put on condom A, then condom B over the top of it. Have sex with woman 1. Remove condom B, turn it inside out and replace. Have sex with woman 2. Remove condom B and have sex with woman 3.

woman 3 just died a horrible death.

the start was right: Put on both condoms. Bang W1. Remove 1 condom. Bang W2. Invert condom 2 and replace. Bang W3.

captcha: bling (as in bling bling ding dong)

• Ken (unregistered) in reply to name
name:
The strategy is for all three people agree to stand in a circle, each looking at the hat of the person in front of them. If the hat is blue, they take off a shoe. If it is red, they do nothing.

So, the three participants enter the room, and after they line up, each person then looks at the feet of the person behind them, counts to 10, and then simultaneously says their color. Where's my \$3 mill?

You don't get any money. You failed to meet the requirements -- specifically the "no communication of any sort is allowed" requirement.

• Mm (unregistered) in reply to vt_mruhlin

one weighing more or less. So binary search gives you nothing. I would put 3 on each side. if: (No movement){ it is one of the two others, one measument is enough to prove witch one it is. } else{ Call all those on the side that went down for X, all those that went up for y, and all those left for z. So you measured 3x vs 3y. Then measure 2x1z vs 1y1x1z. From this, the rest is basic(no mather what happends now, it is easy solvable with one more weight)

• (cs) in reply to name
name:
The strategy is for all three people agree to stand in a circle, each looking at the hat of the person in front of them. If the hat is blue, they take off a shoe. If it is red, they do nothing.

So, the three participants enter the room, and after they line up, each person then looks at the feet of the person behind them, counts to 10, and then simultaneously says their color. Where's my \$3 mill?

400-some posts and people just keep coming up with dumber ideas. Yeah, taking off a shoe isn't communicating. Man you're smart.

• Ken (unregistered) in reply to zip
zip:
name:
The strategy is for all three people agree to stand in a circle, each looking at the hat of the person in front of them. If the hat is blue, they take off a shoe. If it is red, they do nothing.

So, the three participants enter the room, and after they line up, each person then looks at the feet of the person behind them, counts to 10, and then simultaneously says their color. Where's my \$3 mill?

400-some posts and people just keep coming up with dumber ideas. Yeah, taking off a shoe isn't communicating. Man you're smart.
Ooh! Ooh! I know!

Stand in a circle and tell the person to your left the color of their hat. Then everyone can "guess" correctly! You win 100% of the time!

`:-)  :-)  :-)  :-)  :-)  :-)`
• Q.E.D. (unregistered)

The HR guys as well as the project managers have way too much time in their hands. The survival instinct kicks in to save them of a horendous death of boredom and they need a bit of fun with the desperate guy looking for a job. In my \$0.002 opinion, there is no value in these brain teasers, it is a complete nonsense, bullcrap. I can't see your wealth of experience nor your knowledge of the tricks of the trade (the art that is the essence of software projects design and development) if you can ask these stupid qustions. On the long run, you are responsible for delaying the projects, customer service issues and your firing because your smart guy doesn't follow the rules, uses shortcuts - he is to obusy to catch up withe the rest of the team - and has team integration issues due to his superiority complex. I would only use these teasers to remove all the guys who actually answer to this stupid and pointless questions.

• YourMoFoFriend (unregistered) in reply to Ken
Ooh! Ooh! I know! Stand in a circle and tell the person to your left the color of their hat. Then everyone can "guess" correctly! You win 100% of the time!
`:-)  :-)  :-)  :-)  :-)  :-)`
I like your solution :))) I have an even better idea, how about everyone takes their hat off and checks the color when no one is looking... that way everyone will guess correctly and the prize is ours :))).

I swear, from now on I am definitely asking this hat question on all interviews. At least it'll weed out most of the posters here. Just think about it, every poster here insisting on some type of a "cheat", or sticking to "50%" is a software developer somewhere!!! Probably working on something you and I will be using someday!!! Be afraid, be very afraid :)).

• Anonymous Coward (unregistered)

• name (unregistered) in reply to zip

Fine - the only other "correct" answer seems to be to have one predesignated person guess and the other two pass.

The strategy of having two people stand in the corner and the other person joining them if they are the same color will still not indicate who has on which color hat. And again, if we are splitting semantic hairs here about communication, I would classify standing in groups and moving towards or away from that group to pass along information in the same vein as removing an article of clothing.

All the other solutions I've read on here don't seem to qualify the "simultaneous" requirement, so at least give me some credit for that :)

• Devon (unregistered) in reply to Grandpa
Grandpa:
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?

If Person B and Person C are wearing the same color hat, Person A stands next to B, and B says C's color. A & C pass. If B & C have different color hats, A stands next to C, and C says the opposite of B. A & B pass. This may be considered to break the "no communication" rule, but it's dodgy enough that I'd still try to get it past an interviewer.

• YourMoFoFriend (unregistered) in reply to Q.E.D.
Q.E.D.:
In my \$0.002 opinion, there is no value in these brain teasers, it is a complete nonsense, bullcrap.
I think you meant "my \$0.02"? How can you say that there is no value when empirical data (just skim the bloody replies) clearly shows that a LOT of people fail not even at solving, but in UNDERSTANDING of the problem???
• Homie Don't Play That (unregistered)

Q: How many ping pong balls can you fit into a 747?

A: Exactly fuck-you many ping pong balls fit in a 747.

...leaves room to go find a real employer.

• Katalgar (unregistered) in reply to Ken
Ken:
anon:
How about, put 3 and 3 on the balance, keeping 2 aside. If it balances then just compare the 2. Otherwise take the heavy side (3 coins) and compare two, same thing, if they balance it's the odd one out, else you know it's the heavier one. Just 2 weighings, not 3.
Again, re-read the specs. You do not know whether the coin is heavier or lighter.

It's min 2 max 4. Sets are defined as A = 3 coins. B = 3 coins. c = 2 coins. Odd is the odd duck (bad weight coin)

1 is heavier , 0 is lighter, 2 is equal(proper weight) ? is unknown

Weighings | Left Side | Right Side | Aside 1 A v B | A=1 | B=0 | C=? 1 A v B | A=0 | B=1 | C=? 1 A v B | A=2 | B=2 | C=?

2 W1 = 10 | 1/3A=1 | 1/3A=0 | 1/3A=? 2 W1 = 10 | 1/3A=0 | 1/3A=1 | 1/3A=? 2 W1 = 10 | 1/3A=2 | 1/3A=2 | 1/3A=? 2 W1 = 01 | 1/3B=0 | 1/3B=1 | 1/3B=? 2 W1 = 01 | 1/3B=1 | 1/3B=0 | 1/3B=? 2 W1 = 01 | 1/3B=2 | 1/3B=2 | 1/3B=? 2 w1 = 22 | 1/3A=0 | 1/2C=1 ODD | 1/2C=2 2 w1 = 22 | 1/3A=1 | 1/2C=0 ODD | 1/2C=2 2 w1 = 22 | 1/3A=2 | 1/2C=2 | 1/2C=ODD

3 w2!=22 | same=1&odd | aside=2 | right=2 3 w2!=22 | same=0&odd | aside=2 | right=2 3 w2!=22 | same=2 | aside=0&ODD | right=2 3 w2!=22 | same=2 | aside=2&ODD | right=2 3 w2!=22 | same=2 | aside=2 | right=Odd

3 w1=10 w2=22 | 1/3B=1 | 1/3B=0 | 1/3B=2 3 w1=10 w2=22 | 1/3B=0 | 1/3B=1 | 1/3B=2 3 w1=10 w2=22 | 1/3B=2 | 1/3B=2 | 1/3B=ODD 3 w1=01 w2=22 | 1/3A=1 | 1/3A=0 | 1/3A=2 3 w1=01 w2=22 | 1/3A=0 | 1/3A=1 | 1/3A=2 3 w1=01 w2=22 | 1/3A=2 | 1/3A=2 | 1/3A=ODD

4 --same as w3!=22

• (cs) in reply to name
name:
Fine - the only other "correct" answer seems to be to have one predesignated person guess and the other two pass.

The strategy of having two people stand in the corner and the other person joining them if they are the same color will still not indicate who has on which color hat. And again, if we are splitting semantic hairs here about communication, I would classify standing in groups and moving towards or away from that group to pass along information in the same vein as removing an article of clothing.

All the other solutions I've read on here don't seem to qualify the "simultaneous" requirement, so at least give me some credit for that :)

Dear god, you are stupid. The answer is in probably 20 posts in the first 100 replies. It's just mixed in with about another 20 people just like you who think they can cheat by communicating somehow and win.

If you have to worry about whether or not your answer passes the "semantic" constraints of the puzzle, then it doesn't.

• anony coward (unregistered) in reply to Grandpa
Grandpa:
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?

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.

This little piece of syntax here is vague, and the whole challenge centers on it.

What does simultaneously mean?

If it means that all players must guess the color of their own hat the moment any player guesses, the highest odds you have of winning are 1 in 8.

Setting aside the fact that passing may be used for 'communication' which violates the rules of the riddle, after any number of passes there will always be some important pieces of information which cannot be known.

Now if the interviewer thought they had a clever riddle, but mis-worded it, your response to this indicates quite a bit.

In fact, riddles test quite a bit more than thinking ability. If someone grumps about a simple riddle in an initial interview, that may indicate that they will be a difficult employee. Being easily upset or communicating ineffectively will neutralize many if not all other criteria the interviewer is looking for.

If someone storms out of an interview because of a logic test, they may not have failed by missing the logic, but they did fail by not attempting to meet the requirements set. If you are not prepared to meet arbitrary requirements, you will likely be unemployed or underemployed.

• YourMoFoFriend (unregistered) in reply to Homie Don't Play That
Homie Don't Play That:
Q: How many ping pong balls can you fit into a 747? A: Exactly fuck-you many ping pong balls fit in a 747. ...leaves room to go find a real employer.
And what if the company is in the business of filling odd-shaped objects with ping-pong balls? Still walking out? (yeah, I know, if that's what they do you won't even come in for an interview, that's not the point...)
• KJR (unregistered) in reply to Jeff Bell

First, let the chicken eat the grain. Then let the fox eat the chicken.

Now take the fox over the river. The fox contains the chicken which contains the grain. All over in one trip.

Thats efficiency.

• dbavaria (unregistered)

How is this job interview 2.0? This article may as well be from 1999 and it would be more up-to-date.

• anony coward (unregistered) in reply to Grandpa
Grandpa:
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?

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.

This little piece of syntax here is vague, and the whole challenge centers on it.

What does simultaneously mean?

If it means that all players must guess the color of their own hat the moment any player guesses, the highest odds you have of winning are 1 in 8.

Setting aside the fact that passing may be used for 'communication' which violates the rules of the riddle, after any number of passes there will always be some important pieces of information which cannot be known.

Now if the interviewer thought they had a clever riddle, but mis-worded it, your response to this indicates quite a bit.

In fact, riddles test quite a bit more than thinking ability. If someone grumps about a simple riddle in an initial interview, that may indicate that they will be a difficult employee. Being easily upset or communicating ineffectively will neutralize many if not all other criteria the interviewer is looking for.

If someone storms out of an interview because of a logic test, they may not have failed by missing the logic, but they did fail by not attempting to meet the requirements set. If you are not prepared to meet arbitrary requirements, you will likely be unemployed or underemployed.

• Q.E.D. (unregistered) in reply to YourMoFoFriend

Because I look for a guy who manages the programming language first, with a modest understanding of system componenets secondly and thirdly with a good matching prsonality. So, first I ask them to write a simple application and then to make an ODBC connection. And guess what? 80% of them fail, but they know the bloody answers to the teaser test. So I ask you, what need do I have for a guy that can tell me how many zeroes are in 20! (thatis 20 factorial) but he doesn't know how to put a simple app in RAD, c#, with help and internet connection? How much time do I have to allocate to have him up to speed?

• danknerd (unregistered) in reply to I can so relate...
I can so relate...:
Actual questions I got at an interview (not with MS):
• Why is the sky blue?
• How would you estimate the weight of Earth?
• How many people are there in the world?

The sky is blue? Well I am colorblind so I have no way to verify such a thing.

I am sure its in the Bible somewhere, if you believe in such a thing.

Too many.

• Dan (unregistered) in reply to Grandpa

If the two other players are wearing hats of the same color, make the guess the opposite color. If the two other players are different pass.

Assuming the coin is fair you have a 6/8 chance of getting two hats of one color and one hat of another (i.e. two red hats and one blue). Therefore if only the person who see's two hats of the same color guesses the chances of winning are 6/8. Obviously there is a 2/8 chance that all the hats are the same color and everyone guesses and loses.

• (cs) in reply to anony coward
anony coward:

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.

This little piece of syntax here is vague, and the whole challenge centers on it.

What does simultaneously mean?

If it means that all players must guess the color of their own hat the moment any player guesses, the highest odds you have of winning are 1 in 8.

FAIL

"What does simultaneously mean"

ahahahahah yeah that's real ambiguous

• (cs) in reply to anony coward
anony coward:

What does simultaneously mean?

If it means that all players must guess the color of their own hat the moment any player guesses, the highest odds you have of winning are 1 in 8.

Not quite. The problem here is that you're thinking of "passing" in a turn-based manner. A player may say either "red", "blue", or "pass", but all players must give one of those three answers at the same time (simultaneously). So the strategy of passing if you see two hats of differing colors, and guessing the opposite color if you see two hats of the same color, results in winning 6 times out of 8.

• TimS (unregistered) in reply to atari

"o, you disqualify people simply because you are too unoriginal to come up with a ridiculous brain teaser that the candidate has already heard?"

Wow, that's so totally not what I said. You need to read up on "strawman arguments", because you're a natural at making them.

• Flo (unregistered) in reply to Charles Bretana
Charles Bretana:
Actually, the simplification you are remembering from high school calculus is only true when mass distribution satisfies spherical symmetry (i.e. is dependant only on the distance from the center and not on latitude or longitude) This assumption is not 100% true for any real body (the earth included)
No... Mass distribution and shape have an effect on the position of the center of mass. As long as you are outside this object it can be threated as a point mass.

I think we had a prove for that at theoretical physics 1...