Calcudoku puzzle forumhttp://www.calcudoku.org/forum/ "the World's hardest logic/number puzzles"http://www.calcudoku.org/forum/viewtopic.php?f=24&t=463 Page 2 of 3

 Author: main  [ Fri Aug 09, 2013 11:33 am ] Post subject: Re: "the World's hardest logic/number puzzles" This is how I discovered your website, through the duplicate post you published on conceptis puzzles from July 25th.I've been glad I found calcudoku.org ever since. Great way to burn some free time!

 Author: pnm  [ Fri Aug 09, 2013 11:38 am ] Post subject: Re: "the World's hardest logic/number puzzles" main wrote:This is how I discovered your website, through the duplicate post you published on conceptis puzzles from July 25th.I've been glad I found calcudoku.org ever since. Great way to burn some free time!Good to hear, thanks It also got copied to "gizmodo":http://gizmodo.com/can-you-solve-the-10 ... 1064112665Patrick

 Author: nicow  [ Fri Aug 09, 2013 3:28 pm ] Post subject: Re: "the World's hardest logic/number puzzles" Crazydad nr8 is not difficult. After applying simple logic, this puzzles is solved applying Ariadne's Threat in order to eliminate faulty candidates. And more: the first 3 (!) numbers are quite simple to find. So nr8 is only of medium difficulty. I agree with CLM that it's not clear wether a puzzle is more difficult than an other one or not. Because at first there has to be consent to the measuring method. My system solves the 21-12-2012 puzzle in nearly 8 hours (!), after applying Adriadne's Threat, using a search tree. As Dutch men say: "Het is de kift!" Ha ha.

 Author: pnm  [ Sun Aug 11, 2013 9:16 am ] Post subject: Re: "the World's hardest logic/number puzzles" nicow wrote:Crazydad nr8 is not difficult. After applying simple logic, this puzzles is solved applying Ariadne's Threat in order to eliminate faulty candidates. And more: the first 3 (!) numbers are quite simple to findI never knew that "Ariadne's threat" meant guessing & backtracking...(shouldn't it be "thread" ?)nicow wrote:My system solves the 21-12-2012 puzzle in nearly 8 hours (!), after applying Adriadne's Threat, using a search treeThere must be some strategies that can reduce this.For example, my solver works with linear equations of up to 3 unknowns, which can of course be extended to 4, etc.nicow wrote:As Dutch men say: "Het is de kift!" Ha ha.Ik denk het

 Author: nicow  [ Sun Aug 11, 2013 7:11 pm ] Post subject: Re: "the World's hardest logic/number puzzles" pnm wrote:I never knew that "Ariadne's threat" meant guessing & backtracking...(shouldn't it be "thread" ?)Ariadne's thread (indeed with a 'd'), is trying a candidate, and if the result is a faulty solution, this candidate is faulty. Trying all candidates is elaborate, but for a computer that doesn't matter. It is an easy way to clean up all candidates, and many times a good solution is found in the meantime(!). pmn wrote:nicow wrote:My system solves the 21-12-2012 puzzle in nearly 8 hours (!), after applying Adriadne's Threat, using a search treeThere must be some strategies that can reduce this.For example, my solver works with linear equations of up to 3 unknowns, which can of course be extended to 4, etc.Mine does the same, but in an other way, and up to 8 unknowns; this level can be set; 4 happens to be fast, but 6 is more secure in my solver. Of course there can be more strategies implemented. But I search for an optimum: the easy puzzles (and all up to 8x8) are solved within a second or few seconds, so why building in extra logic?But I am building in Row/block-interaction now for the larger puzzles. I'm curious...

 Author: pnm  [ Sun Aug 11, 2013 8:02 pm ] Post subject: Re: "the World's hardest logic/number puzzles" nicow wrote:But I am building in Row/block-interaction now for the larger puzzles. I'm curious...What do you mean by that?(maybe that's already in my solver, maybe not..)Patrick

 Author: nicow  [ Mon Aug 12, 2013 11:49 am ] Post subject: Re: "the World's hardest logic/number puzzles" pnm wrote:nicow wrote:But I am building in Row/block-interaction now for the larger puzzles. I'm curious...What do you mean by that?(maybe that's already in my solver, maybe not..)PatrickIn today's sudoku, candidate 3 in A3 is to be wiped out bij column/block interaction. Here is how: H8=3 so B8 and A8 cannot be a 3. B6=3 so B8 cannot be a 3So, in block 7 value 3 only occurs in row A (A7 and A9)That is why A3 cannot be a 3: in the intersection of row A and block 7 , the value 3 only exists. (By turning the puzzle 90°, column/block is the same as row/block)(edited)

 Author: pnm  [ Mon Aug 12, 2013 6:49 pm ] Post subject: Re: "the World's hardest logic/number puzzles" Interesting, thanks, I'll have to check if I'm already doing this.(thread is going a bit off-topic..)nicow wrote:In today's sudoku, candidate 3 in A3 is to be wiped out bij column/block interaction. Here is how: H8=3 so B8 and A8 cannot be a 3. B7=3 so B8 cannot be a 3You mean B6=3 so B9 cannot be a 3?

 Author: danaburns  [ Fri Aug 16, 2013 8:05 pm ] Post subject: Re: "the World's hardest logic/number puzzles" Is the link in a bad location for anyone else?I have a hard time avoiding it when using the input popup thingie.This is only an issue when I use a small screen device such as a phone.

 Author: pnm  [ Fri Aug 16, 2013 10:38 pm ] Post subject: Re: "the World's hardest logic/number puzzles" danaburns wrote:Is the link in a bad location for anyone else?I have a hard time avoiding it when using the input popup thingie.This is only an issue when I use a small screen device such as a phone.Thanks for letting me know, I'll check this, and mayberemove the link for small devices.Patrick

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