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Introduction

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lehmer is Lehmer code[1] implementation written in Clojure.

You can use it to encode each possible permutation of a

sequence of n numbers.

Installation

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This library can be installed from Clojars[2].

Leiningen/Boot

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[de.dixieflatline/lehmer "0.1.0-SNAPSHOT"]

Example

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  (require '[lehmer.core :as lehmer])

  ;;; Use nth-permutation to compute permutations.

  ;;; lehmer supports distinct lists, vectors and strings.

  (lehmer/nth-permutation 5 "abc")

  => "cab"

  (lehmer/nth-permutation 5 [\a \b \c])

  => [\c \a \b]

  ;;; Provide a permutation and an ordered sequence of available

  ;;; elements to compute the Lehmer code.

  (lehmer/permutation->lehmer-code "cab" "abc")

  => (2 0 0)

  ;;; A Lehmer code can easily be converted to base 10.

  (lehmer/lehmer-code->base-10 [2 0 0])

  => 5

References

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Links

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