43 lines
1.3 KiB
Factor
43 lines
1.3 KiB
Factor
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! Copyright (c) 2012 Anonymous
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! See http://factorcode.org/license.txt for BSD license.
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USING: io kernel math sequences ;
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IN: rosetta-code.sierpinski-triangle
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! http://rosettacode.org/wiki/Sierpinski_triangle
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! Produce an ASCII representation of a Sierpinski triangle of
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! order N. For example, the Sierpinski triangle of order 4 should
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! look like this:
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! *
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! * *
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! * *
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! * * * *
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! * *
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! * * * *
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! * * * *
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! * * * * * * * *
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! * *
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! * * * *
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! * * * *
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! * * * * * * * *
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! * * * *
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! * * * * * * * *
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! * * * * * * * *
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! * * * * * * * * * * * * * * * *
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: iterate-triangle ( triange spaces -- triangle' )
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[ [ dup surround ] curry map ]
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[ drop [ dup " " glue ] map ] 2bi append ;
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: (sierpinski) ( triangle spaces n -- triangle' )
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dup 0 = [ 2drop "\n" join ] [
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[
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[ iterate-triangle ]
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[ nip dup append ] 2bi
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] dip 1 - (sierpinski)
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] if ;
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: sierpinski ( n -- )
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[ { "*" } " " ] dip (sierpinski) print ;
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