defmodule Bracket do
  def bracket(s) do
    result =
      s
      |> String.graphemes()
      |> Enum.reduce_while([], fn ch, stack ->
        case ch do
          ")" -> pop_match(stack, "(")
          "]" -> pop_match(stack, "[")
          "}" -> pop_match(stack, "{")
          _ -> {:cont, [ch | stack]}
        end
      end)

    if result == [], do: 1, else: 0
  end

  defp pop_match([], _expected), do: {:halt, :mismatch}

  defp pop_match([top | rest], expected) do
    if top == expected, do: {:cont, rest}, else: {:halt, :mismatch}
  end
end