aoc2022_day13.santa

input: read("aoc://2022/13")

let parse_packets = lines >> filter(_ != "") >> map(evaluate);

let cmp = |a, b| if a == b { nil } else { a > b }

let compare = |l, r| match [type(l), type(r)] {
  ["List", "Integer"] { compare(l, [r]) }
  ["Integer", "List"] { compare([l], r) }
  ["Integer", "Integer"] { l `cmp` r }
  ["List", "List"] {
    let check = zip(l, r) |> map(|[a, b]| compare(a, b)) |> find(_ != nil);
    if check != nil { check } else { size(l) `cmp` size(r) }
  }
}

part_one: {
  let packet_pairs = parse_packets(input) |> chunk(2);

  zip(1.., packet_pairs)
    |> filter(|[idx, [l, r]]| !compare(l, r))
    |> map(|[idx]| idx)
    |> sum;
}

part_two: {
  let divider_packets = [[[2]], [[6]]];
  let all_packets = parse_packets(input) + divider_packets;

  all_packets
    |> sort(compare)
    |> zip(1.., _)
    |> filter(|[idx, packet]| divider_packets `includes?` packet)
    |> map(|[idx]| idx)
    |> reduce(*);
}

test: {
  input: "[1,1,3,1,1]
[1,1,5,1,1]

[[1],[2,3,4]]
[[1],4]

[9]
[[8,7,6]]

[[4,4],4,4]
[[4,4],4,4,4]

[7,7,7,7]
[7,7,7]

[]
[3]

[[[]]]
[[]]

[1,[2,[3,[4,[5,6,7]]]],8,9]
[1,[2,[3,[4,[5,6,0]]]],8,9]"

  part_one: 13
  part_two: 140
}

test: {
  input: read("aoc://2022/13")
  part_one: 5503
  part_two: 20952
}