Day 6 in pure elixir

Wow so proud of myself this seemed impossible when i started

day5_doublelinked.exs

@@ -18,8 +18,9 @@ defmodule DayFive do
     String.length(poly) - 1
   end
 
-  def react([<<char1>>, <<char2>> | tail], rev) when char1 == char2 - 32 or char2 == char1 - 32,
-    do: react(tail, rev)
+  def react([<<char1>>, <<char2>> | tail], rev)
+      when char1 == char2 - 32 or char2 == char1 - 32,
+      do: react(tail, rev)
 
   def react([<<char1>> | tail], [<<char2>> | rev])
       when char1 == char2 - 32 or char2 == char1 - 32,

day6.exs

@@ -0,0 +1,94 @@
+defmodule DaySix do
+  def part_one(input) do
+    coords = parse_input(input)
+    corners = find_corners(coords)
+    distances = distances(corners, coords)
+    legal = filter_infinite(distances, corners)
+    # IO.puts "Total: #{length distances} Legal: #{length legal}"
+    length = Enum.group_by(legal, fn {_, coord} -> coord end)
+           |> Enum.map(fn {key, list} -> length list end)
+           |> Enum.max
+    length
+  end
+
+  def part_two(input) do
+    coords = parse_input(input)
+    {maxx, maxy, minx, miny} = find_corners(coords)
+    field = gen_field({maxx * 2, maxy * 2, 0, 0})
+    filter_below(field, coords, 10000) |> length
+  end
+
+  def parse_input(input) do
+    lines = String.split(input, "\n")
+      |> Enum.filter(&(&1 != ""))
+    lines
+      |> Enum.map(&(String.split(&1, ", ")))
+      |> Enum.map(fn [x, y] -> {String.to_integer(x), String.to_integer(y)} end)
+  end
+
+  def find_corners(coords) do
+    {maxx, _} = Enum.max_by(coords, fn {x, _} -> x end)
+    {_, maxy} = Enum.max_by(coords, fn {_, y} -> y end)
+    {minx, _} = Enum.min_by(coords, fn {x, _} -> x end)
+    {_, miny} = Enum.min_by(coords, fn {_, y} -> y end)
+
+    {maxx, maxy, minx, miny}
+  end
+
+  def gen_field({maxx, maxy, minx, miny}) do
+    Enum.map(minx..maxx, fn i ->
+      Enum.map(miny..maxy, fn j ->
+        {i, j}
+      end)
+    end) |> List.flatten
+  end
+
+  def distances({maxx, maxy, minx, miny}, coords) do
+    Enum.map(minx..maxx, fn i ->
+      Enum.map(miny..maxy, fn j ->
+        distances = Enum.map(coords, fn {x, y} ->
+          {{x, y}, abs(i - x) + abs(j - y)}
+        end)
+        {{x, y}, distance} = Enum.min_by(distances, fn {_, distance} -> distance end)
+        if length(Enum.filter(distances, fn {_, d} -> distance == d end)) > 1 do
+          []
+        else
+          {{i, j}, {x, y}}
+        end
+      end)
+    end)
+      |> List.flatten
+    # |> Map.new
+  end
+
+  def is_border({maxx, maxy, minx, miny}, {x, y}) when x == maxx or x == minx or y == maxy or y == miny, do: true
+
+  def is_border(_, _), do: false
+
+  def filter_infinite(distances, corners) do
+    is_infinite = Enum.map(distances, fn {{i, j}, {x, y}} -> {{x, y}, is_border(corners, {i, j})} end)
+      |> Enum.group_by(fn {coord, _} -> coord end)
+      |> Enum.map(fn {coord, list} -> {coord, Enum.map(list, fn {_, inf} -> inf end)} end)
+    # IO.inspect is_infinite
+    infinites = is_infinite
+      |> Enum.filter(fn {_, list} -> Enum.member?(list, true) end)
+      |> Enum.map(fn {coord, _} -> coord end)
+    # IO.puts "Infinites: #{length infinites}"
+    Enum.filter(distances, fn {_, coord} -> not Enum.member?(infinites, coord) end)
+  end
+
+  def total_distance({i, j}, points) do
+    Enum.map(points, fn {x, y} -> abs(x - i) + abs(y - j) end) |> List.foldl(0, &+/2)
+  end
+
+  def filter_below(coords, points, under) do
+    total_distances = Enum.map(coords, fn coord -> {coord, total_distance(coord, points)} end)
+    Enum.filter(total_distances, fn {_, dist} -> dist < under end) 
+  end
+
+end
+
+{:ok, content} = File.read("input6.txt")
+
+IO.puts("Part 1: #{DaySix.part_one(content)}")
+IO.puts("Part 2: #{DaySix.part_two(content)}")

input6.txt

@@ -0,0 +1,50 @@
+66, 204
+55, 226
+231, 196
+69, 211
+69, 335
+133, 146
+321, 136
+220, 229
+148, 138
+42, 319
+304, 181
+101, 329
+72, 244
+242, 117
+83, 237
+169, 225
+311, 212
+348, 330
+233, 268
+99, 301
+142, 293
+239, 288
+200, 216
+44, 215
+353, 289
+54, 73
+73, 317
+55, 216
+305, 134
+343, 233
+227, 75
+139, 285
+264, 179
+349, 263
+48, 116
+223, 60
+247, 148
+320, 232
+60, 230
+292, 78
+247, 342
+59, 326
+333, 210
+186, 291
+218, 146
+205, 246
+124, 204
+76, 121
+333, 137
+117, 68