First time trying to do anything in elixir. I’m still learning in early stage and sometimes it twist my mind to be able to express what i want to do. I think i overcomplicated it a lot, but at least got the correct result 
defmodule Aoc2024.Day1 do
def getresult do
{:ok, contents} = File.read("input")
# [ %{left: 40094, right: 37480}, %{left: 52117, right: 14510}, ... ]
itemlist =
contents
|> String.split("\n")
|> Enum.map(fn(line) -> splitlist(line) end)
# Sorted list with only left values
left_items =
itemlist
|> Enum.sort(fn(i1, i2) -> order_items(i1, i2, :left) end)
|> Enum.map(fn(i) -> i.left end)
# same for the right values
right_items =
itemlist
|> Enum.sort(fn(i1, i2) -> order_items(i1, i2, :right) end)
|> Enum.map(fn(i) -> i.right end)
# List of diff of each left and right value at the same list position
difflist =
Enum.zip(left_items, right_items)
|> Enum.map(fn{li, ri} -> abs(li - ri) end)
# sum the values via recursive add
add_values(difflist, 0)
end
defp splitlist(line) do
[left , right] = line |> String.split(" ", trim: true)
%{left: String.to_integer(left) , right: String.to_integer(right)}
end
defp order_items(i1, i2, side) do
case side do
:left -> i1.left <= i2.left
:right -> i1.right <= i2.right
end
end
defp add_values([h | t], result) do
h + add_values(t, result)
end
defp add_values([], result) do
result
end
end
IO.puts(Integer.to_string(Aoc2024.Day1.getresult))
.
