[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: n-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? > 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 And this is what you get in the 554KB .zip file: $ 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 $ Mit besten Gruessen / Best wishes, 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 From: Hermann Stamm-Wilbrandt/Germany/IBM@IBMDE To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx, Date: 04/23/2012 10:35 AM Subject: Re: n-queens? > 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#post2 2269 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? Mit besten Gruessen / Best wishes, 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 From: "Mark" <mark@xxxxxxxxxxxx> To: <xsl-list@xxxxxxxxxxxxxxxxxxxxxx>, Date: 04/21/2012 08:25 PM Subject: Re: n-queens? 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: 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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