Untitled notebook

Section

defmodule Solution do
  @spec max_rep_opt1(text :: String.t()) :: integer
  def max_rep_opt1(text) do
    letters = text |> String.graphemes()

    groups =
      letters
      |> Enum.chunk_by(& &1)
      |> Enum.map(&{hd(&1), Enum.count(&1)})

    counts = letters |> Enum.frequencies()

    max_1 =
      groups
      |> Enum.map(fn {k, v} ->
        min(v + 1, Map.get(counts, k))
      end)
      |> Enum.max()

    max(
      max_1,
      groups
      |> Enum.chunk_every(3, 1, :discard)
      |> Enum.reduce(
        0,
        fn [{k1, v1}, {_k2, v2}, {k3, v3}], acc ->
          max(
            acc,
            if(k1 == k3 and v2 == 1, do: min(v1 + v2 + v3, Map.get(counts, k1)), else: acc)
          )
        end
      )
    )
  end
end

Solution.max_rep_opt1("abbbbaab")