Day 3. Part 1 broken

day3.exs

@@ -0,0 +1,70 @@
+defmodule DayThree do
+
+  def parse_claim(claim) do
+    pattern = ~r/#(\d+) @ (\d+),(\d+): (\d+)x(\d+)/
+    [ [ _ | match ] ] = Regex.scan(pattern, claim)
+    [id, x, y, xwidth, ywidth] = Enum.map(match, &(String.to_integer(&1)))
+
+    {id, x, y, xwidth, ywidth}
+  end
+
+  def part_one(input) do
+    claims = String.split(input, "\n")
+      |> Enum.filter(&(&1 != ""))
+      |> Enum.map(&DayThree.parse_claim/1)
+    IO.puts "dupes"
+    dupes = new_doubles(claims)
+      |> Enum.dedup
+    area_with = dupes
+      |> Enum.map(fn {_, {_, _, dx, dy}} -> dx * dy end)
+      |> List.foldl(0, &+/2)
+    area_with
+  end
+
+  def new_doubles(claims) do
+    Enum.map(claims, fn {id1, x1, y1, dx1, dy1} ->
+      Enum.map(claims, fn {id2, x2, y2, dx2, dy2} ->
+        {{:id, id1, id2}, intersect({x1, y1, dx1, dy1}, {x2, y2, dx2, dy2})}
+      end) |> Enum.filter(fn {_, square} -> square != nil end)
+    end)
+      |> List.flatten
+      |> Enum.filter(fn {_, square} -> square != nil end)
+  end
+
+  def intersect({x1, y1, dx1, dy1}, {x2, y2, dx2, dy2}) do
+    if {x1, y1, dx1, dy1} == {x2, y2, dx2, dy2} do
+      nil
+    else
+      xe1 = x1 + dx1
+      xe2 = x2 + dx2
+      ye1 = y1 + dy1
+      if x2 <= xe1 && y2 <= ye1 && x2 >= x1 && y2 >= y1 do
+        {y2, x2, xe1 - x2, ye1 - y2}
+      else if xe2 >= x1 && y2 <= ye1 && x2 <= x1 && y2 >= y1 do
+        {x1, y2, xe2 - x1, ye1 - y2}
+        else
+          nil
+        end
+      end
+    end
+  end
+
+  def part_two(input) do
+    claims = String.split(input, "\n")
+      |> Enum.filter(&(&1 != ""))
+      |> Enum.map(&DayThree.parse_claim/1)
+    IO.puts "dupes"
+    dupes = new_doubles(claims)
+      |> Enum.dedup
+      |> Enum.map(fn {{:id, id1, id2}, _} -> [id1, id2] end)
+      |> List.flatten
+    claim_id = Enum.map(claims, fn {id, _, _, _, _} -> id end)
+    [id] = Enum.filter(claim_id, &(not Enum.member?(dupes, &1)))
+    id
+  end
+end
+
+{:ok, content} = File.read "input3.txt"
+
+IO.puts "Part 1: #{DayThree.part_one(content)}"
+IO.puts "Part 2: #{DayThree.part_two(content)}"