48 lines
638 B
Text
48 lines
638 B
Text
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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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test := <<2, 5, 1>>
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permute (test, 1)
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end
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test: ARRAY [INTEGER]
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permute (a: ARRAY [INTEGER]; k: INTEGER)
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-- All permutations of 'a'.
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require
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count_positive: a.count > 0
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k_valid_index: k > 0
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local
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t: INTEGER
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do
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if k = a.count then
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across
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a as ar
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loop
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io.put_integer (ar.item)
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end
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io.new_line
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else
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across
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k |..| a.count as c
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loop
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t := a [k]
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a [k] := a [c.item]
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a [c.item] := t
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permute (a, k + 1)
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t := a [k]
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a [k] := a [c.item]
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a [c.item] := t
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end
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end
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end
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end
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