Submission #17277396

---

Source Code Expand

defmodule Main do
  @words ~w(dream dreamer erase eraser) |> Enum.map(&String.reverse/1)

  def main do
    IO.read(:line)
    |> String.trim()
    |> solve()
    |> IO.puts()
  end

  @doc ~S"""
  https://atcoder.jp/contests/abc085/tasks/abc085_b

  ## Examples

      iex> Abc049C.solve("erasedream")
      "YES"
      iex> Abc049C.solve("dreameraser")
      "YES"
      iex> Abc049C.solve("dreamerer")
      "NO"

  """
  def solve(s) do
    String.reverse(s) |> do_solve()
  end

  defp do_solve(""), do: "YES"

  defp do_solve(nil), do: "NO"

  defp do_solve(s) do
    @words
    |> Enum.reduce_while(nil, fn word, acc ->
      if String.starts_with?(s, word) do
        {:halt, String.slice(s, String.length(word)..-1)}
      else
        {:cont, acc}
      end
    end)
    |> do_solve()
  end
end

Submission Info

Judge Result