Subject: Re: [xsl] n-queens? From: "Mark" <mark@xxxxxxxxxxxx> Date: Mon, 23 Apr 2012 10:04:36 -0700 |
So for the first problem the count of all positions with 5, 6 and 7queens
threatening all fields seem to be what you are interested in, right?I went ahead and modified n-queens.xsl.xml to solve exactly this problem.
This is the output of 8-queens-maximal.text.xsl.xml: ----------------------------------------------------- maximal positions 10188 8-queens solutions 92 "less than 8"-queens maximal positions 10096 5-queens maximal positions 728 6-queens maximal positions 6912 7-queens maximal positions 2456
Some facts on running this on Thinkpad W520 with 64bit Linux: 1) Opening 8-queens-maximal.text.xsl.xml in a freshly started Firefox (10) just takes 8sec(!) and uses 738MB of resident memory.
Opening 8-queens-maximal.text.xsl.xml in a freshly started Chrome (18) just takes 5sec(!) and uses 4MB(!!) of resident memory.
2) The saved file HTML page for 8-queens-maximal.xsl.xml is of size 52.8GB(!).
3) Just loading 8-queens-maximal.xsl.xml.html into a freshly started Firefox takes 2:03min and uses 1.8GB of resident memory.
Just loading 8-queens-maximal.xsl.xml.html into a freshly started Chrome takes 29sec and uses 1.0GB of resident memory.
4) Opening 8-queens-maximal.xsl.xml in a freshly started Firefox takes 2:31min and uses 3.2GB of resident memory.
Opening 8-queens-maximal.xsl.xml in a freshly started Google Chrome 18 takes 43sec and uses 1.1GB of resident memory.
These are the links: http://stamm-wilbrandt.de/en/xsl-list/n-queens/8-queens-maximal.text.xsl.xml.html http://stamm-wilbrandt.de/en/xsl-list/n-queens/8-queens-maximal.text.xsl.xml http://stamm-wilbrandt.de/en/xsl-list/n-queens/8-queens-maximal.xsl.xml http://stamm-wilbrandt.de/en/xsl-list/n-queens/8-queens-maximal.zip
$ unzip -l 8-queens-maximal.zip Archive: 8-queens-maximal.zip Length Date Time Name --------- ---------- ----- ---- 10082 04-23-2012 17:55 8-queens-maximal.text.xsl.xml 392 04-23-2012 18:07 8-queens-maximal.text.xsl.xml.html 10056 04-23-2012 18:00 8-queens-maximal.xsl.xml 0 04-23-2012 18:35 8-queens-maximal.xsl.xml_files/ 55334374 04-23-2012 18:36 8-queens-maximal.xsl.xml.html 97 04-23-2012 18:35 8-queens-maximal.xsl.xml_files/b.gif 345 04-23-2012 18:35 8-queens-maximal.xsl.xml_files/bqb.gif 545 04-23-2012 18:35 8-queens-maximal.xsl.xml_files/bqw.gif 96 04-23-2012 18:35 8-queens-maximal.xsl.xml_files/w.gif --------- ------- 55355987 9 files $
Hermann Stamm-Wilbrandt Level 3 support for XML Compiler team and Fixpack team lead WebSphere DataPower SOA Appliances https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/ ---------------------------------------------------------------------- IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294
This puzzle, although interesting, is commonly given to beginning programming students.
Yes, but I posted here because of "XSLT 1.0 + exslt:node-set()" solution and the two questions I have (Muenchian grouping / functional style).
I remember facing it myself. One I have never seen solved are the number of boards where less than eight queens is the maximum.
Please be more precise on what you count as "a board". Does the board contain less than 8 queens for your problem? Or does the board always contain 8 queens, some threatening another?
In the latter case the answer is: (64 choose 8) - 92 = 4426165368
Long ago I posted some queen-puzzles on a (German language) chess forum. Here you can see a position with 5 queens threatening all fields: http://www.schachmatt.de/69-schachraetsel/2764-3xdamen-uberdeckung.html#post22269
It is not possible to threaten all fields with only 4 queens. So for the first problem the count of all positions with 5, 6 and 7 queens threatening all fields seem to be what you are interested in, right?
Hermann Stamm-Wilbrandt Level 3 support for XML Compiler team and Fixpack team lead WebSphere DataPower SOA Appliances https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/ ---------------------------------------------------------------------- IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294
This puzzle, although interesting, is commonly given to beginning programming students. I remember facing it myself. One I have never seen solved are the number of boards where less than eight queens is the maximum. Mark
-----Original Message----- From: Ivan Shmakov Sent: Saturday, April 21, 2012 8:26 AM To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx Cc: Ivan Shmakov Subject: Re: [xsl] n-queens?
Michael Hopwood <michael@xxxxxxxxxxx> writes:
I'm no chess OR maths expert but - surely they are not actually chess queens if any two of the same colour can threaten each other? The puzzle using actual chess queens, at least one of which is of the other colour, would look quite different...
AIUI, for the purposes of this puzzle, /each/ of the queens is assumed to be of its own distinct colour.
--cut: http://en.wikipedia.org/wiki/Eight_queens_puzzle -- The eight queens puzzle is the problem of placing eight chess queens on an 8W8 chessboard so that no two queens attack each other. Thus, a solution requires that no two queens share the same row, column, or diagonal. The eight queens puzzle is an example of the more general n-queens problem of placing n queens on an nWn chessboard, where solutions exist for all natural numbers n with the exception of 2 and 3. --cut: http://en.wikipedia.org/wiki/Eight_queens_puzzle --
-- FSF associate member #7257
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