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Guest Message by DevFuse

Prisoners sorting cards - this puzzle is not for the faint of heart

Best Answer Yoruichi-san, 16 August 2014 - 05:28 AM

I had done the same analysis as Barc and concluded that it's probably the correct answer because

Spoiler for

As for coming up with a different strategy
Spoiler for
That said, I bet bonanova's already thought of that and has a solution that still works with those rules despite my argument that attempts to show it's impossible.

plasmid gives me too much credit, so I'm going to out myself now and state that this is adapted from genius puzzler who will be credited when the solution is found. This is done to keep Google out of the competition, not that anyone would do that.   Further, I worked on this puzzle until I convinced myself that I could not solve it before looking at the solution. So you guys are the heroes here, not me.

1. plasmid's first paragraph makes me wonder. His mirror point seems valid, and it's possible
that my adaptation opened a loophole. If so, a slight modification of the OP avoids it:

The first prisoner solves the puzzle and writes an algorithm on a piece of paper that he leaves in the room.
In that case, and if there are in fact multiple solutions, then Prisoner 1 selects one that they all will use.
In that case, any algorithm that gives AKQ will be a correct solution to the puzzle.
That is, it won't be required that every prisoner would have found the same algorithm (if there are several) and used it.

Or we could say the prisoners are allowed to discuss a strategy beforehand.

2. I can provide a helpful clue, one that still leaves a very hard problem, if desired.

Maybe I'm missing something, but I think this might oversimplify the problem.  If I can select a specific direction, I think I can get to AKQ in 6 moves from any initial formation, regardless of the time.

Spoiler for Strategy
Go to the full post

21 replies to this topic

#11 plasmid

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Posted 16 August 2014 - 03:45 AM

That makes it easy to guarantee release if the prisoners still get to know what time of day they enter the room.
Want to take away their watches so they're all forced to follow the same algorithm without knowing when they've entered?
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#12 Yoruichi-san

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Posted 16 August 2014 - 05:28 AM   Best Answer

I had done the same analysis as Barc and concluded that it's probably the correct answer because

Spoiler for

As for coming up with a different strategy
Spoiler for
That said, I bet bonanova's already thought of that and has a solution that still works with those rules despite my argument that attempts to show it's impossible.

plasmid gives me too much credit, so I'm going to out myself now and state that this is adapted from genius puzzler who will be credited when the solution is found. This is done to keep Google out of the competition, not that anyone would do that.   Further, I worked on this puzzle until I convinced myself that I could not solve it before looking at the solution. So you guys are the heroes here, not me.

1. plasmid's first paragraph makes me wonder. His mirror point seems valid, and it's possible
that my adaptation opened a loophole. If so, a slight modification of the OP avoids it:

The first prisoner solves the puzzle and writes an algorithm on a piece of paper that he leaves in the room.
In that case, and if there are in fact multiple solutions, then Prisoner 1 selects one that they all will use.
In that case, any algorithm that gives AKQ will be a correct solution to the puzzle.
That is, it won't be required that every prisoner would have found the same algorithm (if there are several) and used it.

Or we could say the prisoners are allowed to discuss a strategy beforehand.

2. I can provide a helpful clue, one that still leaves a very hard problem, if desired.

Maybe I'm missing something, but I think this might oversimplify the problem.  If I can select a specific direction, I think I can get to AKQ in 6 moves from any initial formation, regardless of the time.

Spoiler for Strategy

• 0
Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

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#13 Barcallica

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Posted 16 August 2014 - 05:32 AM

That makes it easy to guarantee release if the prisoners still get to know what time of day they enter the room.
Want to take away their watches so they're all forced to follow the same algorithm without knowing when they've entered?

Or force them to make move.
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#14 bonanova

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Posted 16 August 2014 - 01:29 PM

Don't see that it matters.

The configuration dictates the move, not the time of day.

The solution is not "If it's 3:00 then place the Q on top of the A."

With a random warden, Prisoner 1 might make the winning move.

Y-San's post tells the nature of the solution, so let's just pose it that way:

Arrange the configurations into categories of your choice, then give the correct move for each case.

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Vidi vici veni.

#15 bonanova

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Posted 16 August 2014 - 01:50 PM

Y-San, do your steps have a cycle?

Spoiler for for example

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Vidi vici veni.

#16 Yoruichi-san

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Posted 16 August 2014 - 05:56 PM

Y-San, do your steps have a cycle?

Spoiler for for example

Spoiler for Steps

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Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

<3 BBC's Sherlock, the series and the man. "Smart is the new sexy."

Chromatic Witch links now on my 'About Me' page! Episode 3 is finally here!

When life hands me lemons, I make invisible ink.

#17 Barcallica

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Posted 18 August 2014 - 03:22 AM

Spoiler for My thought was

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#18 Yoruichi-san

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Posted 18 August 2014 - 05:45 AM

Lol...please don't describe me or anything I do as "slick" .  I'm an engineer, so I tend to be partial towards adjectives that start with 'e', i.e. 'elegant', 'efficient', or 'enigmatic' ;P.

It occurs to me that not everyone might intuitively think of directions in terms of connectivity instead of absolute physical position, so it helps conceptually...

Spoiler for Wrapping one's head around 'wrapping around

• 0
Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

<3 BBC's Sherlock, the series and the man. "Smart is the new sexy."

Chromatic Witch links now on my 'About Me' page! Episode 3 is finally here!

When life hands me lemons, I make invisible ink.

#19 bonanova

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Posted 20 August 2014 - 05:49 PM

Marking it solved, but ...

Spoiler for confusion on step 4

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Vidi vici veni.

#20 Yoruichi-san

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Posted 20 August 2014 - 07:20 PM

Sure, revise away...

Although I have to respectfully disagree .  I think if you fully embrace the idea of 'wrapping around' no revision is necessary.

I.e. The earth 'wraps around'.  Europe is technically both to the west and the east of Asia.  However, if you ask any Asian, they'll tell you Europe is to the west, which is b/c 1) it's closer on the west and 2) it's connected to the west.

"Of the pair" is referring to the pair of cards (since you only see two cards when you walk into the room), which also makes more sense in the previous terms since, in my mind at least, it implies the cards are adjacent. I.e. if you see A_Q and you think of it in terms of ...A_QA_QA_QA_QA_QA_QA_QA_Q..., the "pair" is pretty obvious.  *shrugs*

Anyways, what was the original problem?  I feel like based on what you've said, it should have a pirate-game-esque solution, but I'm not seeing it here. I'm very interested in what it might be.

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Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

<3 BBC's Sherlock, the series and the man. "Smart is the new sexy."

Chromatic Witch links now on my 'About Me' page! Episode 3 is finally here!

When life hands me lemons, I make invisible ink.

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