{ lib, utils, ... }:
with lib;
with builtins;
with utils;
let
  numbers = map (l: map toInt (splitWhitespace l)) (readLines ./input);
  left = sort lessThan (map (flip elemAt 0) numbers);
  right = sort lessThan (map (flip elemAt 1) numbers);
in {
  part1 = listSum (zipListsWith delta left right);
  part2 = listSum (map (x: x * (count (eq x) right)) left);
}