[Elixir] adventofcode 2018 Day 3

2018_d3.exs

#Part 1
 data = ["#1 @ 429,177: 12x27", "#2 @ 862,948: 20x11", "#3 @ 783,463: 22x20"]
data |> Enum.map(fn str ->
  [_, data] = String.split(str, "@")
  [point, range] = String.split(data, ":")
  [top, right] = String.split(point, ",")
  [xs, ys] = String.split(range, "x")

  [top, right, xs, ys]
  |> Enum.map(&String.trim/1)
  |> Enum.map(&String.to_integer/1)
  |> List.to_tuple()
end) |> Enum.map(fn {top, right, xs, ys} ->
  Enum.map(0..(xs - 1), fn x ->
    Enum.map(0..(ys - 1), fn y ->
      {top + x, right + y}
    end)
  end)
end) |> List.flatten()  |> Enum.reduce(%{}, fn x, acc -> 
  Map.update(acc, x, 0, &(&1 + 1)) 
end)|> Enum.filter(fn {_, v} -> 
  v != 0 
end) |> Enum.count



# Part 2


indices = tangle |> Enum.map(&elem(&1, 0))

sub = 
 tangle |> Enum.map(fn {index, top, right, xs, ys} ->
  Enum.map(0..(xs - 1), fn x ->
    Enum.map(0..(ys - 1), fn y ->
      {index, top + x, right + y}
    end)
  end)
end) |> List.flatten()  |> Enum.reduce(%{}, fn {i,x,y}, acc -> 
  Map.update(acc, {x, y}, [i], &([i|&1])) 
end)


tangle |> Enum.map(fn {index, top, right, xs, ys} ->
  Enum.map(0..(xs - 1), fn x ->
    Enum.map(0..(ys - 1), fn y ->
      {index, top + x, right + y}
    end)
  end)
end) |> List.flatten() |> Enum.reduce(indices, fn {index, x, y}, acc -> 
  value = Map.get(sub, {x, y})
  if value != [index] do
    List.delete(acc, index)
  else
    acc
  end
end)