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  1. let inverseFizzBuzz input =
  2.     let lcmWord, lcmNumber = "fizzbuzz", 15
  3.     let partialResultMap =
  4.         [0 .. lcmNumber] |> List.choose (fun n ->
  5.             match n % 3, n % 5 with
  6.             | 0, 0 -> Some("fizzbuzz", n)
  7.             | 0, _ -> Some("fizz", n)
  8.             | _, 0 -> Some("buzz", n)
  9.             | _ -> None)
  10.         |> fun ls -> [1 .. ls.Length] |> Seq.collect (fun n -> Seq.windowed n ls)
  11.         |> Seq.map (Array.unzip >> fun (f, s) -> List.ofArray f, [|s.[s.Length - 1]; s.[0]|])
  12.         |> Seq.sortBy (snd >> Array.reduce (-))
  13.         |> Seq.distinctBy fst
  14.         |> Map.ofSeq
  15.         |> Map.add [lcmWord] [|lcmNumber; lcmNumber|]
  16.  
  17.     let getPartialResult start words =
  18.         Map.tryFind words partialResultMap |> Option.map (Array.map ((+) start))
  19.  
  20.     (Array.ofSeq input, []) |> Seq.unfold (function
  21.     | [||], _ -> None
  22.     | words, first ->
  23.         match Array.tryFindIndex ((=) lcmWord) words with
  24.         | Some i -> Some(first @ List.ofArray words.[.. i], (words.[i + 1 ..], [lcmWord]))
  25.         | None -> Some(first @ List.ofArray words, ([||], [lcmWord])))
  26.     |> Seq.toArray
  27.     |> Array.mapi ((*) lcmNumber >> getPartialResult)
  28.     |> function
  29.     | xs when Array.forall Option.isSome xs -> Some(xs.[0].Value.[1], xs.[xs.Length - 1].Value.[0])
  30.     | _ -> None
  31.  
  32. [
  33.     ["fizz"]
  34.     ["buzz"]
  35.     ["fizzbuzz"]
  36.     ["fizz"; "buzz"]
  37.     ["buzz"; "fizz"]
  38.     ["fizz"; "buzz"; "fizz"]
  39.     ["fizz"; "fizz"]
  40.     ["fizz"; "fizz"; "buzz"]
  41.     ["buzz"; "buzz"]
  42.     ["fizz"; "fizzbuzz"]
  43.     ["fizzbuzz"; "fizz"]
  44.     ["fizz"; "fizzbuzz"; "fizz"]
  45.     ["fizzbuzz"; "fizz"; "buzz"; "fizz"; "fizz"; "buzz"; "fizz"; "fizzbuzz"]
  46.     ["fizz"; "fizzbuzz"; "fizz"; "buzz"; "fizz"; "fizz"; "buzz"; "fizz"; "fizzbuzz"; "fizz"; "buzz"; "fizz"; "fizz"; "buzz"; "fizz"; "fizzbuzz"; "fizz"; "buzz"]
  47.     [""]
  48.     ["abc"]
  49. ] |> List.map inverseFizzBuzz |> List.zip [
  50.     Some(3, 3)
  51.     Some(5, 5)
  52.     Some(15, 15)
  53.     Some(9, 10)
  54.     Some(5, 6)
  55.     Some(3, 6)
  56.     Some(6, 9)
  57.     Some(6, 10)
  58.     None
  59.     Some(12, 15)
  60.     Some(15, 18)
  61.     Some(12, 18)
  62.     Some(15, 30)
  63.     Some(12, 50)
  64.     None
  65.     None
  66. ] |> List.tryFind ((<||) (<>))
  67. |> printfn "%A"
Success #stdin #stdout 0.22s 13112KB
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<null>
https://ideone.com/Y4i7U
language:
F# (mono 4.1)
created:
11 years ago
visibility:
public

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