From 307a9d41d955d8ee00fb03d7eef039a7251d2a8c Mon Sep 17 00:00:00 2001
From: Justin Wernick <justin@worthe-it.co.za>
Date: Fri, 11 Oct 2024 13:45:26 +0200
Subject: Optimize day 19 part 1. Still no luck on part 2.

---
 2015/day19.exs | 56 +++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 11 deletions(-)

diff --git a/2015/day19.exs b/2015/day19.exs
index 2aae946..d73c9c0 100644
--- a/2015/day19.exs
+++ b/2015/day19.exs
@@ -1,11 +1,42 @@
+defmodule Tokenizer do
+  use Agent
+
+  def start do
+    Agent.start_link(fn -> {0, %{}} end, name: __MODULE__)
+  end
+
+  def tokenize(raw) do
+    strTokens = List.flatten(Regex.scan(~r/[eA-Z][a-z]*/, raw))
+
+    Enum.map(strTokens, fn strToken ->
+      {lastToken, token} =
+        Agent.get(__MODULE__, fn {lastToken, map} -> {lastToken, Map.get(map, strToken)} end)
+
+      if token do
+        token
+      else
+        token = lastToken + 1
+        Agent.update(__MODULE__, fn {_, map} -> {token, Map.put(map, strToken, token)} end)
+        token
+      end
+    end)
+  end
+end
+
+{:ok, _} = Tokenizer.start()
+
 {replacements, medicine} =
   File.stream!("inputs/day19.txt")
   |> Stream.map(&String.trim/1)
   |> Stream.filter(&(&1 != ""))
   |> Stream.map(fn line ->
     case Regex.run(~r/(\w+) => (\w+)/, line) do
-      [_, from, to] -> {:replacement, from, to}
-      _ -> {:start, line}
+      [_, from, to] ->
+        [from] = Tokenizer.tokenize(from)
+        {:replacement, from, Tokenizer.tokenize(to)}
+
+      _ ->
+        {:start, Tokenizer.tokenize(line)}
     end
   end)
   |> Enum.reduce({[], nil}, fn
@@ -14,24 +45,27 @@
   end)
 
 nextGen = fn start ->
-  Enum.flat_map(0..(String.length(start) - 1), fn offset ->
-    {beforeReplace, replaceStart} = String.split_at(start, offset)
+  Enum.flat_map(0..(length(start) - 1), fn offset ->
+    {beforeReplace, [replaceStart | afterReplace]} = Enum.split(start, offset)
 
-    Enum.filter(replacements, fn {from, _} -> String.starts_with?(replaceStart, from) end)
-    |> Enum.map(fn {from, to} ->
-      {^from, afterReplace} = String.split_at(replaceStart, String.length(from))
-      <<beforeReplace <> to <> afterReplace>>
+    Enum.filter(replacements, fn {from, _} -> replaceStart == from end)
+    |> Enum.map(fn {_, to} ->
+      beforeReplace ++ to ++ afterReplace
     end)
   end)
-  |> Enum.uniq()
 end
 
-calibration = nextGen.(medicine)
+calibration = Enum.uniq(nextGen.(medicine))
 
 IO.puts("Calibration size: #{length(calibration)}")
 
 medicineGeneration =
-  Stream.iterate(["e"], fn gen -> Enum.flat_map(gen, &nextGen.(&1)) |> Enum.uniq() end)
+  Stream.iterate([Tokenizer.tokenize("e")], fn gen ->
+    Enum.flat_map(gen, &nextGen.(&1))
+    |> Enum.filter(&(length(&1) <= length(medicine)))
+    |> Enum.uniq()
+  end)
+  |> Stream.each(&IO.inspect("#{length(&1)}"))
   |> Enum.find_index(fn gen -> Enum.any?(gen, &(&1 == medicine)) end)
 
 IO.puts("The Medicine generation: #{medicineGeneration}")
-- 
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