create 2023 dir

lib/2023/2023_day1.ex

@@ -50,8 +50,8 @@ defmodule Day1_2024 do
       0,
       fn i, _ ->
         cur_char = l |> String.at(len - i)
-        IO.puts("examining ")
-        IO.puts(cur_char)
+        # IO.puts("examining ")
+        # IO.puts(cur_char)
         int_at_pos = cur_char |> Integer.parse()
 
         case int_at_pos do
@@ -74,7 +74,7 @@ defmodule Day1_2024 do
   end
 
   def search_for_written_number(line) do
-    IO.puts("searching " <> line)
+    # IO.puts("searching " <> line)
 
     numbers = [
       "one",
@@ -111,7 +111,7 @@ defmodule Day1_2024 do
         end)
         |> Enum.filter(&(&1 |> elem(1) |> Enum.count() > 1))
 
-      IO.puts(inspect(splits))
+      # IO.puts(inspect(splits))
 
       number_word =
         splits

lib/2023/2023_day2_2.exs

@@ -0,0 +1,24 @@
+max = %{"red" => 12, "green" => 13, "blue" => 14}
+
+is_valid_pull = fn {count, color} ->
+  count <= max[color]
+end
+
+for {id, pulls} <-
+      (for line <- IO.stream(),
+           String.trim(line) != "",
+           "Game " <> game = line,
+           {id, ": " <> rest} = Integer.parse(game) do
+         {id,
+          for pull <- String.split(rest, "; ") |> Enum.map(&String.trim/1),
+              cube <- String.split(pull, ", ") |> Enum.map(&String.trim/1),
+              {count, color} = Integer.parse(cube),
+              color = String.trim(color) do
+            {count, color}
+          end}
+       end),
+    Enum.all?(pulls, &is_valid_pull.(&1)) do
+  id
+end
+|> Enum.sum()
+|> IO.puts()

lib/2023/2023_day3.ex

@@ -0,0 +1,54 @@
+import RegexUtil, only: [scan_index_with_binary: 2]
+
+defmodule Mix.Tasks.Day3 do
+  use Mix.Task
+
+  @r_digits ~r/\d+/
+
+  def run(_) do
+    part2(IO.stream()) |> IO.puts()
+  end
+
+  def contains_symbol(s) do
+    Regex.match?(~r/[^\d.]/, s)
+  end
+
+  def part1(s) do
+    for [pre, curr, post] <-
+          s
+          |> then(fn x -> Enum.concat([""], x) end)
+          |> Enum.chunk(3, 1)
+          |> Enum.map(fn u -> Enum.map(u, &String.trim/1) end),
+        [{index, length}] <- Regex.scan(@r_digits, curr, return: :index),
+        contains_symbol(String.slice(curr, max(index - 1, 0), length + 2)) ||
+          contains_symbol(String.slice(pre, max(index - 1, 0), length + 2)) ||
+          contains_symbol(String.slice(post, max(index - 1, 0), length + 2)),
+        {number, _} = String.slice(curr, index, length) |> Integer.parse() do
+      number
+    end
+    |> Enum.sum()
+  end
+
+  def part2(s) do
+    for [pre, curr, post] <-
+          s
+          |> Enum.chunk(3, 1)
+          |> Enum.map(fn u -> Enum.map(u, &String.trim/1) end),
+        curr |> String.contains?("*"),
+        [{gear_idx, _}] <- Regex.scan(~r/\*/, curr, return: :index),
+        matches =
+          scan_index_with_binary(@r_digits, pre)
+          |> Enum.concat(scan_index_with_binary(@r_digits, post))
+          |> Enum.concat(scan_index_with_binary(@r_digits, curr)),
+        valid_matches =
+          matches
+          |> Enum.filter(fn {m_idx, m_len, _} ->
+            gear_idx in max(0, m_idx - 1)..(m_idx + m_len)
+          end),
+        valid_matches |> Enum.count() == 2,
+        [{_, _, a}, {_, _, b}] = valid_matches do
+      a * b
+    end
+    |> Enum.sum()
+  end
+end

lib/2023/2023_day3.exs

@@ -27,6 +27,8 @@ part1 = fn s ->
   |> Enum.sum()
 end
 
+r_digits = ~r/\d+/
+
 part2 = fn s ->
   for [pre, curr, post] <-
         s
@@ -36,7 +38,9 @@ part2 = fn s ->
       curr |> String.contains?("*"),
       [{gear_idx, _}] <- Regex.scan(~r/\*/, curr, return: :index),
       matches =
-        grab_numbers.(pre) |> Enum.concat(grab_numbers.(post)) |> Enum.concat(grab_numbers.(curr)),
+        grab_numbers.(pre)
+        |> Enum.concat(grab_numbers.(post))
+        |> Enum.concat(grab_numbers.(curr)),
       valid_matches =
         matches
         |> Enum.filter(fn {m_idx, m_len, _} ->
@@ -49,4 +53,4 @@ part2 = fn s ->
   |> Enum.sum()
 end
 
-part2.(IO.stream()) |> IO.puts()
+part1.(IO.stream()) |> IO.puts()

lib/2023/2023_day4.ex

@@ -19,8 +19,8 @@ defmodule Card do
 
   def parse(input) do
     for card <- input |> String.split("\n"),
-      card != "",
-      [winning_numbers, our_numbers] = parse_card(card) do
+        card != "",
+        [winning_numbers, our_numbers] = parse_card(card) do
       [winning_numbers, our_numbers]
     end
   end