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ToLehmerCode ​

Entry i counts the later entries smaller than p(i).

WikipediaLehmer codeWikidataQ2981462Rosetta CodePermutations/Rank of a permutation

ToLehmerCode(Permutation)

Domain: Combinatorial maps

Details
  • Takes a `Permutation` and returns a `SubexcedantSeq` — a typed map, so a wrong carrier is a type error rather than a wrong answer.
  • Its total is the inversion count, which is the Lehmer code's whole point.

Examples