diff --git a/lib/run_length_encoding.ex b/lib/run_length_encoding.ex index d32c5a3..02a7a6c 100644 --- a/lib/run_length_encoding.ex +++ b/lib/run_length_encoding.ex @@ -1,16 +1,16 @@ defmodule RunLengthEncoding do - @doc """ - Generates a string where consecutive elements are represented as a data value and count. - "AABBBCCCC" => "2A3B4C" - For this example, assume all input are strings, that are all uppercase letters. - It should also be able to reconstruct the data into its original form. - "2A3B4C" => "AABBBCCCC" - """ - require Logger + require IEx - def encode(string) do + def encode(string) when string == "" do + "" end - def decode(string) do + def encode(string) do + %{"head" => head, "tail" => tail} = Regex.named_captures(~r/(?#{String.at(string,0)}+)(?.*)/, string) + if String.length(head) == 1 do + "#{head}#{encode(tail)}" + else + "#{String.length(head)}#{String.at(head, 0)}#{encode(tail)}" + end end end diff --git a/test/run_length_encoding_test.exs b/test/run_length_encoding_test.exs index 68ca48c..4301805 100644 --- a/test/run_length_encoding_test.exs +++ b/test/run_length_encoding_test.exs @@ -6,28 +6,23 @@ defmodule RunLengthEncodingTest do assert RunLengthEncoding.encode("") === "" end - @tag :pending test "encode single characters only are encoded without count" do assert RunLengthEncoding.encode("XYZ") === "XYZ" end - @tag :pending test "encode string with no single characters" do assert RunLengthEncoding.encode("AABBBCCCC") == "2A3B4C" end - @tag :pending test "encode single characters mixed with repeated characters" do assert RunLengthEncoding.encode("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB") === "12WB12W3B24WB" end - @tag :pending test "encode multiple whitespace mixed in string" do assert RunLengthEncoding.encode(" hsqq qww ") === "2 hs2q q2w2 " end - @tag :pending test "encode lowercase characters" do assert RunLengthEncoding.encode("aabbbcccc") === "2a3b4c" end