defmodule StoneBlocks do
  def stone_blocks(h) do
    {_stack, blocks} =
      Enum.reduce(h, {[], 0}, fn height, {stack, blocks} ->
        stack = Enum.drop_while(stack, &(&1 > height))

        case stack do
          [^height | _] -> {stack, blocks}
          _ -> {[height | stack], blocks + 1}
        end
      end)

    blocks
  end
end