2024/22 optimizations

elixir/livebook/2024/day22.livemd

@@ -8,7 +8,8 @@
 
 ```elixir
 input = """
-"""
+""" |> String.split("\n", trim: true)
+|> Enum.map(&String.to_integer/1)
 ```
 
 ## Section
@@ -17,13 +18,41 @@ input = """
 defmodule MonkeyMarket do
   @doc """
   
+  ## Example
+  iex> MonkeyMarket.enc_base19([-1,0,9,-9]) 
+  -9+10+20*(19+20*(10+20*(9)))
+  """
+  def enc_base19(ints) do
+    ints
+    |> Enum.reduce(
+      0,
+      fn i, acc -> acc * 20 + i + 10 end
+    )
+  end
+
+  
+  @doc """
+  ## Example
+  iex> MonkeyMarket.dec_base19(-9+10+20*(19+20*(10+20*(9)))) 
+  [-1,0,9,-9]
+  """
+  def dec_base19(i) do
+    dec_base19(i, [])
+  end
+  defp dec_base19(0, acc), do: acc
+  defp dec_base19(i, acc) do
+    dec_base19(div(i,20),[Integer.mod(i, 20)-10 | acc])
+  end
+  
+  @doc """
+  
   ## Example
   iex> MonkeyMarket.part2([1,2,3,2024])
   23
   """
   def part2(input) do
-    for m <- (
+    tasks = for j <- input do
-      for j <- input do
+      Task.async(fn -> 
         diffs = MonkeyMarket.next(j, 2000)
         |> Stream.map(&rem(&1, 10))
         |> Enum.reverse()
@@ -33,12 +62,14 @@ defmodule MonkeyMarket do
       for [_,_,_,{n,_}] = chunk <- diffs 
         |> Stream.chunk_every(4, 1, :discard),
         chunk = chunk |> Enum.map(&(elem(&1, 1))),
-          
         reduce: %{} do
         acc2 ->
-            acc2 |> Map.update(chunk, n, &(&1))
+          acc2 |> Map.put_new(chunk |> enc_base19, n)
           end 
-      end), reduce: %{} do
+      end)
+    end
+    
+    for m <- Task.await_many(tasks, :infinity), reduce: %{} do
       acc -> Map.merge(
         m,
         acc,
@@ -74,13 +105,13 @@ defmodule MonkeyMarket do
 end
 ```
 
+```elixir
+MonkeyMarket.part2(input)
+```
+
 ```elixir
 Benchee.run(%{
   part1: fn -> MonkeyMarket.part1(input) end
 })
 
 ```
-
-```elixir
-MonkeyMarket.part2(input)
-```