Tuning Trouble

Mix.install([{:kino, "~> 0.7.0"}])

Implementation

search = fn input, size ->
  index =
    Enum.chunk_every(String.to_charlist(input), size, 1)
    |> Enum.find_index(fn packet -> length(Enum.uniq(packet)) == length(packet) end)

  index + size
end

Examples

7 == search.("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 4)
5 == search.("bvwbjplbgvbhsrlpgdmjqwftvncz", 4)
6 == search.("nppdvjthqldpwncqszvftbrmjlhg", 4)
10 == search.("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 4)
11 == search.("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 4)

19 == search.("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 14)
23 == search.("bvwbjplbgvbhsrlpgdmjqwftvncz", 14)
23 == search.("nppdvjthqldpwncqszvftbrmjlhg", 14)
29 == search.("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 14)
26 == search.("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 14)

:pass

Input

input = Kino.Input.textarea("Input:")

input = Kino.Input.read(input)

Part 1

search.(input, 4)

Part 2

search.(input, 14)