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\if{\let{!\defined{key}{N} || \N < 1}}{
\write{stderr}{device}{Use e.g. zoem -i 8q2 -s N=9 to solve the 9-queen problem\@{\N}}
\set{N}{8}
}{}
\setx{N}{\let{floor(\N)}}
\def{pp#1}{\%{ass}{\1}}
\set{ptr}{0}
\set{%{ass}{-1}}{0}
\setx{row_odd}{\seq{n}{0}{\N}{\if{\let{\n%2}}{.}{-} }}
\setx{row_even}{\seq{n}{0}{\N}{\if{\let{\n%2}}{-}{.} }}
\set{n}{0}
\while{\let{\n<=\N}}{
\set{%{ass}{\n}}{0}
\setx{n}{\let{\n+1}}
}
\set{n}{0}
\while{\let{\n<=\N}}{
\setx{n}{\let{\n+1}}
}
\set{id}{0}
\while{\let{\ptr>=0}}{
\set{i}{0}
\while{\let{
\i<\ptr
&& \%{ass}{\i} != \%{ass}{\ptr}
&& \%{ass}{\i} - \%{ass}{\ptr} != \ptr - \i
&& \%{ass}{\i} - \%{ass}{\ptr} != \i - \ptr
}
}{\setx{i}{\let{\i+1}}}
\branch{
{\let{\i==\N-1}}
{ \set{t}{0}
\while{\let{\t<\N}}{
\setx{t2}{\if{\let{\t % 2}}{\row_odd}{\row_even}}
\set{{start}{\let{2*\pp{\t}}}{width}{1}}{t2}{W}
\write{\__fnout__}{device}{\t2\@{\n}}
\setx{t}{\let{\t+1}}
}
\setx{id}{\let{\id+1}}
\write{\__fnout__}{device}{(\id)\@{\P}}
}
{\let{\i==\ptr}}
{ \setx{ptr}{\let{\ptr+1}}
\set{%{ass}{\ptr}}{-1}
}
}
\while{\let{\ptr>=0 && \%{ass}{\ptr} == \N-1}}{
\set{%{ass}{\ptr}}{0}
\setx{ptr}{\let{\ptr-1}}
}
\setx{%{ass}{\ptr}}{\let{\%{ass}{\ptr}+1}}
}
|
