Sha256: 2187faf8a14ed21febcf16e9c0667deed00176a1efaeba2aee1c05dd449e5892
Contents?: true
Size: 1.09 KB
Versions: 133
Compression:
Stored size: 1.09 KB
Contents
module RunLengthEncoding
open System
let digitToInt c = int c - int '0'
let partitionConsecutive list =
let folder item acc =
match acc with
| (x::xs)::ys when x = item -> (item::x::xs) :: ys
| _ -> [item] :: acc
List.foldBack folder list []
let encode (input: string) =
let encodePartition (partition: char list) =
match partition with
| [x] -> string x
| x::_ -> sprintf "%i%O" (List.length partition) x
| _ -> failwith "Can't encode empty partition"
input.ToCharArray()
|> List.ofArray
|> partitionConsecutive
|> List.map encodePartition
|> List.fold (+) ""
let decode (input: string) =
let folder ((decoded: string), (count: int option)) item =
let updatedCount = Option.fold (fun acc x -> acc + x * 10) (digitToInt item) count |> Some
let updateDecoded = Option.fold (fun acc x -> acc + String(item, x - 1)) (decoded + string item) count
if Char.IsDigit item then (decoded, updatedCount) else (updateDecoded, None)
input
|> Seq.fold folder ("", None)
|> fst
Version data entries
133 entries across 133 versions & 1 rubygems