This is the exact question I got when I was flown out to MS for an interview.
I got it correct during the interview. There are multiple different ways to think of it but I got it by thinking of everyday life. Think of how we pay and get change for purchases. You should then be able to figure it out.
After a while I realized that CHMOD also is a way to think about it.
EDIT: The simplest way is usually correct. There is no reason to bend it or anythig like that. Just think outside of the box. This is a brute force problem. It just takes a little thinking.
I got it correct during the interview. There are multiple different ways to think of it but I got it by thinking of everyday life. Think of how we pay and get change for purchases. You should then be able to figure it out.
After a while I realized that CHMOD also is a way to think about it.
EDIT: The simplest way is usually correct. There is no reason to bend it or anythig like that. Just think outside of the box. This is a brute force problem. It just takes a little thinking.
umm, it's been answered already. I like the CHMOD connection though
4-2-1, it's really quite natural when you think about it.... CHMOD couldn't be handled in any other way.We (a large software company) ask brainteasers all the time in our interviews for software engineers. As some people pointed out, the point is simply to see how you think.
Usually we ask someone a question and then tell them to describe out loud how they'd go about solving the problem. People rarely if ever get them correct (it's a high pressure situation, we understand that) without some help, and we don't mind nudging them in the right direction.
But it is AMAZING... some people would get this question and go "um.. I dunno, maybe cut them in half twice... then you'd get 4.. is 4 close enough? There's no real answer. It's impossible." which is the WRONG answer.
The people that think things out and logically explain some various scenarios will get prodded to go in the right direction, and usually they'll figure things out quickly enough. We almost always tell them the right answer in the end, and if they go "OHHHHH" that's good. If they go "I don't get it" and just have a blank look on their face...
I recall from my interview that I needed a good bit of nudging, but I had the concepts approximately correct so it was all good.
Usually we ask someone a question and then tell them to describe out loud how they'd go about solving the problem. People rarely if ever get them correct (it's a high pressure situation, we understand that) without some help, and we don't mind nudging them in the right direction.
But it is AMAZING... some people would get this question and go "um.. I dunno, maybe cut them in half twice... then you'd get 4.. is 4 close enough? There's no real answer. It's impossible." which is the WRONG answer.
The people that think things out and logically explain some various scenarios will get prodded to go in the right direction, and usually they'll figure things out quickly enough. We almost always tell them the right answer in the end, and if they go "OHHHHH" that's good. If they go "I don't get it" and just have a blank look on their face...
I recall from my interview that I needed a good bit of nudging, but I had the concepts approximately correct so it was all good.
my friend who got interviewed by microsfot today got a different question - u have 9 balls and one of them is lighter. how do u find out the lighter one using a scale only twice
If the manager can only cut the bar twice a week then get the worker to cut it the rest of the time.
Will
Will
how much emphasis do u put in brain teasers when you decide who to hire?
cause I used to do a lot of brain teasers for fun and I dont think I have ever not solved one or at least came very close to solving one, but im afraid id jus buckle in a high pressure situation like that. its like taking a hard test with ur pants down and everyone looking at you.
Hayabusa Rider
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Thats not too hard. Divide the balls into three groups(3*3). Weigh one group. If one group is lighter, then the lightest ball is in that group otherwise the third group has the lightest ball. Divide the group with the lightest ball into 3 balls and weigh any two. The scale will show which ball is lighter among the two otherwise if both the balls are equal in weight then the third ball is lightest. TWO STEPS!
How should the manager solve this problem??
Easy, and Im sure someone has come up with this Pay them once a week and you dont have to cut any bars.
I was to lazy to read all the posts.
Easy, and Im sure someone has come up with this Pay them once a week and you dont have to cut any bars.
I was to lazy to read all the posts.
nope, uw
who did you guys get interviewed by? my guy was pretty high up, so it was pretty nice and relaxed. i've heard that some of the lower people can be a little... not fun.
Originally posted by: GoodToGo
Thats not too hard. Divide the balls into three groups(3*3). Weigh one group. If one group is lighter, then the lightest ball is in that group otherwise the third group has the lightest ball. Divide the group with the lightest ball into 3 balls and weigh any two. The scale will show which ball is lighter among the two otherwise if both the balls are equal in weight then the third ball is lightest. TWO STEPS!
"Weigh one group. If one group is lighter..."
Lighter than what?
Also you neglected the second group.
The answer is even simpler than you think....You can see the ball that has a lighter color.
har har just kiddin
Originally posted by: element®
Originally posted by: GoodToGo
Thats not too hard. Divide the balls into three groups(3*3). Weigh one group. If one group is lighter, then the lightest ball is in that group otherwise the third group has the lightest ball. Divide the group with the lightest ball into 3 balls and weigh any two. The scale will show which ball is lighter among the two otherwise if both the balls are equal in weight then the third ball is lightest. TWO STEPS!
"Weigh one group. If one group is lighter..."
Lighter than what?
Also you neglected the second group.
The answer is even simpler than you think....You can see the ball that has a lighter color.
har har just kiddin
lighter than the other group... he meant to say balance instead of scale.
Oh I see with a balance scale that makes sense.
I was just trying to think outside the x-box with the off-color joke.
I was just trying to think outside the x-box with the off-color joke.
Here is one more which a friend of mine has been asked at the MS interview:
"You have two room and a hallway between them. In one room you have 2 switches, and in another one you have 3 light bulbs. You can go through the hallway only once, from room with switches to the room with light bulbs. You can's see one room from another. Your goal is to determine which switch control which light bulb."
"You have two room and a hallway between them. In one room you have 2 switches, and in another one you have 3 light bulbs. You can go through the hallway only once, from room with switches to the room with light bulbs. You can's see one room from another. Your goal is to determine which switch control which light bulb."
my friend got interviewed today by them also ... soda hall, eh? =) good luck on the first rounds!
Ummm, that last problem, am I to assume that word "can's" is "can't" ?
both switches: run to next room and see two lights on - can't decide which switch is which....
no switches: run to next room - feel like idiot
one switch: run to next room, realize you know one light and switch combo... other two lights are a mystery (50/50).
Can't sneak into the other room and unscrew anything because you're not allowed back to the switches.
Are two lights connected to the same switch? If that were the case you could throw one switch and see either one or two lights on... that'd tell you right away and is rather simple.
Solution?
both switches: run to next room and see two lights on - can't decide which switch is which....
no switches: run to next room - feel like idiot
one switch: run to next room, realize you know one light and switch combo... other two lights are a mystery (50/50).
Can't sneak into the other room and unscrew anything because you're not allowed back to the switches.
Are two lights connected to the same switch? If that were the case you could throw one switch and see either one or two lights on... that'd tell you right away and is rather simple.
Solution?
How bout turn switch 1 on for a long time, then turn it off. THen turn on switch 2 and go to the other room. THe light bulb that is on is controlled by switch 2. and the lightbulb that is off but is warm to the touch is controlled by switch 1.
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