Math Puzzle Thread - DiscussWorldIssues - Socio-Economic Religion and Political Uncensored Debate

**77rexulceme** · 02-26-2007, 01:08 AM

Are you sure they can't signal in any way? Not even to say "I haven't figured it out yet"?

**hansen384cbh** · 02-26-2007, 01:10 AM

**erepsysoulperj** · 02-26-2007, 01:11 AM

Bastard

**goolen4you** · 02-26-2007, 01:13 AM

Wait, but you can guess and get it wrong but not die until everyone has guessed?

**13spebampiliece** · 02-26-2007, 01:14 AM

Nope.

**exiceJetLip** · 02-26-2007, 01:15 AM

The first prisoner looks at the second prisoner's hat and "guesses" that colour, then the second prisoner proceeds to set them all free.

edit: quite an x-post

**Gogogo** · 02-26-2007, 01:16 AM

To which of those questions? Your second set. No communication means no communication.

**carletoxtrs** · 02-26-2007, 01:16 AM

If I can't hear what the guess is, then you label the colors from 1 to N. If the last guy is color 1, the first guy guesses anything. If 2, the second guy... etc. By the end the last guy knows what color he is.

**Pharmadryg** · 02-26-2007, 01:18 AM

I saw this problem first about a year ago, but the context in which I saw it seemed to imply that it was not a very well-known problem. Where did you hear it?

**DeronBoltonRen** · 02-26-2007, 01:21 AM

LS is tricky

**sallythetolly** · 02-26-2007, 01:22 AM

Originally posted by civman2000
I saw this problem first about a year ago, but the context in which I saw it seemed to imply that it was not a very well-known problem. Where did you hear it? It's a variation on one I've seen a few times before.

**Tw1anJOO** · 02-26-2007, 01:22 AM

What if a prisoner is colour-blind?

**FLOMOUSLY** · 02-26-2007, 01:22 AM

ill be back... and if no one else answers when i come back, i WILL have one...

**zdoppiklonikaa** · 02-26-2007, 01:33 AM

Originally posted by Kuciwalker

*****. If 1 through N-1 guess incorrectly, does he kill everyone? You might as well say that all N people guess simultaneously. If at least one of them is correct, they all live; if they're all wrong, they all die.

**isogeople** · 02-26-2007, 01:39 AM

Originally posted by civman2000
You might as well say that all N people guess simultaneously. If at least one of them is correct, they all live; if they're all wrong, they all die. Oh, I guess that works just as well as guessing in order.

**Kamepherype** · 02-26-2007, 01:40 AM

I was drinking heavily. But to demonstrate that I'm not full of ****, I'll show you a solution for N = 2:

Person 1 guesses Person 2's color
Person 2 guesses the opposite of Person 1's color

**violalmina** · 02-26-2007, 01:50 AM

You're on the right track (or at least one of them)...

**inofindy** · 02-26-2007, 01:58 AM

The function has to take into account the order. Consider the cases that all but one are red and the last blue, and all be one are red and the last green. Any function of just "what is everyone else wearing" would have them all make the same guess (and not telling the last guy which color he was), so it must also be a function of their respective positions.

**ChexEcodece** · 02-26-2007, 02:01 AM

i see what you mean Kuciwalker...

**Nmoitmzr** · 02-26-2007, 02:03 AM

Originally posted by Krill
Is the person allowed to look at all of the other hats so that he knows the distribution of the colours? If each individual person can do this, each person simply notes which colour is the most common and everyone says that. After the hats have been given out the people don;t have to communicate. You have no information about the distribution.

02-26-2007, 01:08 AM	#1
77rexulceme Join Date Oct 2005 Posts 504 Senior Member	Math Puzzle Thread Are you sure they can't signal in any way? Not even to say "I haven't figured it out yet"? Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:10 AM	#2
hansen384cbh Join Date Oct 2005 Posts 418 Senior Member	Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:11 AM	#3
erepsysoulperj Join Date Oct 2005 Posts 387 Senior Member	Bastard Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:13 AM	#4
goolen4you Join Date Oct 2005 Posts 447 Senior Member	Wait, but you can guess and get it wrong but not die until everyone has guessed? Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:14 AM	#5
13spebampiliece Join Date Oct 2005 Posts 522 Senior Member	Nope. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:15 AM	#6
exiceJetLip Join Date Oct 2005 Posts 409 Senior Member	The first prisoner looks at the second prisoner's hat and "guesses" that colour, then the second prisoner proceeds to set them all free. edit: quite an x-post Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:16 AM	#7
Gogogo Join Date Oct 2005 Posts 393 Senior Member	To which of those questions? Your second set. No communication means no communication. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:16 AM	#8
carletoxtrs Join Date Oct 2005 Posts 436 Senior Member	If I can't hear what the guess is, then you label the colors from 1 to N. If the last guy is color 1, the first guy guesses anything. If 2, the second guy... etc. By the end the last guy knows what color he is. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:18 AM	#9
Pharmadryg Join Date Oct 2005 Posts 435 Senior Member	I saw this problem first about a year ago, but the context in which I saw it seemed to imply that it was not a very well-known problem. Where did you hear it? Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:21 AM	#10
DeronBoltonRen Join Date Oct 2005 Posts 412 Senior Member	LS is tricky Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:22 AM	#11
sallythetolly Join Date Oct 2005 Posts 421 Senior Member	Originally posted by civman2000 I saw this problem first about a year ago, but the context in which I saw it seemed to imply that it was not a very well-known problem. Where did you hear it? It's a variation on one I've seen a few times before. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:22 AM	#12
Tw1anJOO Join Date Oct 2005 Posts 404 Senior Member	What if a prisoner is colour-blind? Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:22 AM	#13
FLOMOUSLY Join Date Oct 2005 Posts 354 Senior Member	ill be back... and if no one else answers when i come back, i WILL have one... Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:33 AM	#14
zdoppiklonikaa Join Date Oct 2005 Posts 495 Senior Member	Originally posted by Kuciwalker *****. If 1 through N-1 guess incorrectly, does he kill everyone? You might as well say that all N people guess simultaneously. If at least one of them is correct, they all live; if they're all wrong, they all die. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:39 AM	#15
isogeople Join Date Oct 2005 Posts 476 Senior Member	Originally posted by civman2000 You might as well say that all N people guess simultaneously. If at least one of them is correct, they all live; if they're all wrong, they all die. Oh, I guess that works just as well as guessing in order. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

02-26-2007, 01:40 AM	#16
Kamepherype Join Date Oct 2005 Posts 461 Senior Member	I was drinking heavily. But to demonstrate that I'm not full of ****, I'll show you a solution for N = 2: Person 1 guesses Person 2's color Person 2 guesses the opposite of Person 1's color Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:50 AM	#17
violalmina Join Date Oct 2005 Posts 365 Senior Member	You're on the right track (or at least one of them)... Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 01:58 AM	#18
inofindy Join Date Oct 2005 Posts 473 Senior Member	The function has to take into account the order. Consider the cases that all but one are red and the last blue, and all be one are red and the last green. Any function of just "what is everyone else wearing" would have them all make the same guess (and not telling the last guy which color he was), so it must also be a function of their respective positions. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 02:01 AM	#19
ChexEcodece Join Date Oct 2005 Posts 471 Senior Member	i see what you mean Kuciwalker... Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote

02-26-2007, 02:03 AM	#20
Nmoitmzr Join Date Oct 2005 Posts 717 Senior Member	Originally posted by Krill Is the person allowed to look at all of the other hats so that he knows the distribution of the colours? If each individual person can do this, each person simply notes which colour is the most common and everyone says that. After the hats have been given out the people don;t have to communicate. You have no information about the distribution. Share Share this post on Digg Del.icio.us Technorati Twitter
	Quote