advent_of_code/day1.ex

43 lines
911 B
Elixir

defmodule Exercise1 do
def to_command(s) do
try do
{:add, s |> String.trim() |> String.to_integer()}
rescue
ArgumentError -> {:reset}
end
end
def get_answer(state) do
elem(state, 1) |>
Enum.reduce(0, fn i, acc -> i + acc end)
end
def init_state() do
{nil, [0, 0, 0], false}
end
def apply_command(command, state) do
case command do
{:add, n} -> apply_add(n, state)
{:reset} -> apply_reset(state)
end
end
defp apply_add(n, state) do
{current, total, exit} = state
new_current = if is_nil(current) do 0 else current end + n
new_total = [ new_current | total ] |>
Enum.sort(:desc) |>
Enum.take(3)
{new_current, new_total, exit}
end
defp apply_reset(state) do
{current, total, exit} = state
case current do
nil -> {current, total, true}
_ -> {nil, total, exit}
end
end
end