Sha256: 280909617946919eac18155235f50f01956c8fc53b7e1d3f5fe5ee645b54ab76
Contents?: true
Size: 769 Bytes
Versions: 396
Compression:
Stored size: 769 Bytes
Contents
module RailFenceCipher
open System
let track rails index =
let size = rails * 2 - 2
let correct i = i % size = 0
if correct index then 0
elif correct (index - rails + 1) then rails - 1
else [1 .. (rails - 2)] |> List.find (fun i -> correct (index - i) || correct (index - size + i))
let encode rails message =
message
|> Seq.mapi (fun i c -> track rails i, c)
|> Seq.groupBy fst
|> Seq.map (fun (_, sequence) -> sequence|> Seq.map snd |> Array.ofSeq |> String)
|> Seq.reduce (fun x y -> x + y)
let decode rails (message: string) =
[0 .. message.Length - 1]
|> Seq.groupBy (track rails)
|> Seq.collect snd
|> Seq.zip message
|> Seq.sortBy snd
|> Seq.map (fst >> string)
|> Seq.reduce (+)
Version data entries
396 entries across 396 versions & 1 rubygems