day10 part 1

lib/day10.ex

@@ -0,0 +1,69 @@
+import Integer, only: [mod: 2]
+
+defmodule Day10 do
+  @behaviour Solution
+
+  def init_state(_) do
+    %{ vm: VirtualMachine.new(), acc: 0 }
+  end
+
+  def execute(line, state) when line == "" do
+    state
+  end
+
+  def execute(line, state) do
+    VirtualMachine.plan_execute(line) |>
+    Enum.reduce(
+      state,
+      fn (tock, %{vm: vm, acc: acc}) ->
+        next_tick = vm.tick + 1
+        acc = if (next_tick - 20 |> mod(40)) === 0, do: acc + (next_tick) * vm.x, else: acc
+        vm = tock.(vm)
+        %{ vm: vm, acc: acc}
+      end
+    )
+  end
+
+  def get_answer(state) do
+    state.acc
+  end
+end
+
+defmodule VirtualMachine do
+  def new() do
+    %{ x: 1, tick: 0 }
+  end
+
+  def plan_execute(instruction) do
+    [instruction, args] = if instruction == "noop" do 
+      [instruction, nil]
+    else 
+      String.split(instruction, " ") 
+    end
+
+    plan_execute(instruction, args)
+  end
+
+  def plan_execute(instruction, args) when instruction == "addx" do
+    args = case Integer.parse(args) do
+      {args, _} -> args
+      :error -> 0
+    end
+    if is_integer(args) do
+      plan_execute("noop", nil) ++ 
+      [
+        fn (vm) -> 
+          vm |> 
+            Map.update(:tick, 2, &(&1 + 1)) |>
+            Map.update(:x, args, &(&1 + args))
+        end
+      ]
+    else []
+    end
+  end
+
+  def plan_execute(instruction, _) when instruction == "noop" do
+    [fn (vm) -> Map.update(vm, :tick, 1, &(&1 + 1)) end]
+  end
+end
+

main.exs

@@ -1 +1 @@
-AOCRunner.run(Day9, :part2)
+AOCRunner.run(Day10, :part1)