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jawher/s99-P26.clj

Created July 9, 2010 00:24
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s99-P26.clj
(defn permutations "P26" [n xs]
(if (= 1 n)
(map list xs)
(reduce #(let [s (split-at (inc %2) xs)
ps (permutations (dec n) (last s))
a (last (first s))]
(concat %1 (map (fn [p] (cons a p)) ps )))
'() (range 0 (inc (- (count xs) n))))
))
(permutations 6 '(\a \b \c \d \e \f \g \h))
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