35 lines
571 B
Text
35 lines
571 B
Text
class
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APPLICATION
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create
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make
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feature {NONE}
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make
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do
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across
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0 |..| 14 as c
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loop
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io.put_double (nth_catalan_number (c.item))
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io.new_line
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end
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end
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nth_catalan_number (n: INTEGER): DOUBLE
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--'n'th number in the sequence of Catalan numbers.
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require
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n_not_negative: n >= 0
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local
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s, t: DOUBLE
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do
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if n = 0 then
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Result := 1.0
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else
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t := 4 * n.to_double - 2
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s := n.to_double + 1
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Result := t / s * nth_catalan_number (n - 1)
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end
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end
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end
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