If you use an easier markup, for example
<n-queens>
<q c="1" r="3"/>
<q c="2" r="1"/>
<q c="3" r="4"/>
<q c="4" r="2"/>
</n-queens>
which denotes your board with 4 queens in the specified row and
column, then I think the following single xpath works for any size
board and evaluates to true if every column has a queen, every row
has a queen and the number of distinct falling and rising diagonals
with a queen equals the number of queens.
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
<xsl:template match="n-queens">
<xsl:sequence select="
(every $c in 1 to count(q) satisfies exists(q[@c=$c])) and
(every $r in 1 to count(q) satisfies exists(q[@r=$r])) and
count(q)=count(distinct-values(q/(number(@r) - number(@c)))) and
count(q)=count(distinct-values(q/(number(@r) + number(@c))))
"/>
</xsl:template>
</xsl:stylesheet>
you could easily make that into a schematron assertion.
On 1 April 2017 at 23:19, David Carlisle <d.p.carlisle@gmail.com> wrote:
<column1><row>3</row></column1>
why the horrible asymmetry in the markup, with the column number in the
element name and the row number in element content?
That defeats most ways of shortening the schema by exploiting the symmetry
in the problem.
David
