advent-of-code/2021/nim/day22.nim

import ./common, std/[sequtils, algorithm, sugar, sets, strformat, strutils, tables, options, json, hashes, random, pegs]

const BOARD_POSITIONS = 10

type
  Vec3 = tuple[x: int, y: int, z: int]
  Cuboid = tuple[pos: Vec3, size: Vec3]
  CuboidGeometry = HashSet[Cuboid]

  CuboidOperator = enum union, difference
  CuboidOperation = (CuboidOperator, Cuboid)

let parser = peg"""
grammar <- {'on' / 'off'} ' x=' range ',y=' range ',z=' range
range <- {num} \. \. {num}
num <- ('-' \d+) / \d+
"""

proc apply(a: Vec3, b: Vec3, f: (int, int) -> int): Vec3 = (x: f(a.x, b.x), y: f(a.y, b.y), z: f(a.z, b.z))
proc `+`(a: Vec3, b: Vec3): Vec3 = a.apply(b, (a, b) => a + b)
proc `-`(a: Vec3, b: Vec3): Vec3 = a.apply(b, (a, b) => a - b)
proc `*`(a: Vec3, b: Vec3): Vec3 = a.apply(b, (a, b) => a * b)
proc min(a: Vec3, b: Vec3): Vec3 = a.apply(b, (a, b) => min(a, b))
proc max(a: Vec3, b: Vec3): Vec3 = a.apply(b, (a, b) => max(a, b))

proc parseCuboidOperator(s: string): CuboidOperator =
  if s[1] == 'n': union else: difference

proc parse(s: string): Option[CuboidOperation] =
  if s =~ parser:
    let
      n = matches[1..6].map parseInt
      pos = (x: min(n[0], n[1]), y: min(n[2], n[3]), z: min(n[4], n[5]))
      size = (x: max(n[0], n[1]), y: max(n[2], n[3]), z: max(n[4], n[5])) - pos
    result = some (matches[0].parseCuboidOperator, (pos, size))

proc vertices(c: Cuboid): array[6, Vec3] =
  result[0] = c.pos
  result[1] = c.pos + (c.size * (x: 1, y: 0, z: 0))
  result[2] = c.pos + (c.size * (x: 0, y: 1, z: 0))
  result[3] = c.pos + (c.size * (x: 0, y: 0, z: 1))
  result[4] = c.pos + (c.size * (x: 1, y: 1, z: 0))
  result[5] = c.pos + (c.size * (x: 1, y: 1, z: 1))

proc contains(a: Cuboid, b: Vec3): bool =
  b.x >= a.pos.x and b.x <= (a.pos.x + a.size.x) and
    b.y >= a.pos.y and b.y <= (a.pos.y + a.size.y) and
    b.z >= a.pos.z and b.z <= (a.pos.z + a.size.z)

proc contains(a: Cuboid, b: Cuboid): bool = b.vertices.allIt a.contains it
proc intersects(a: Cuboid, b: Cuboid): bool = a.vertices.anyIt b.contains it

proc split(a: Cuboid, b:Cuboid): array[0..26, Cuboid] =
  # find segments along each axis as subdivision points
  let minpos = min(a.pos, b.pos)
  let maxpos = max(a.pos, b.pos)

proc `+=`(a: var CuboidGeometry, b: Cuboid) =
  var g = toHashSet([b])
  var toExcl = initHashSet[Cuboid]()
  for ac in a:
    block nextg:
      var nextG = g
      for gc in g:
        if ac.contains gc: break nextg
        elif gc.contains ac: toExcl.incl ac
        elif ac.intersects gc:
          # TODO: split and add to gc
          # TODO: remove this
          break nextg
      g = nextG
  a = (a - toExcl) + g

proc `-=`(a: var CuboidGeometry, b: Cuboid) =
  var g = toHashSet([b])
  var toExcl = initHashSet[Cuboid]()
  for ac in a:
    block nextg:
      for gc in g:
        if gc.contains ac:
          toExcl.incl ac
        elif ac.contains gc:
          # TODO: split and add to ac
          break nextg
        elif ac.intersects gc:
          # TODO: split and add to ac, may not need to be separate from above
          break nextg
  a = (a - toExcl) + g

proc p1(input: Lines): uint64 =
  let bounds = (pos: (x: -50, y: -50, z: -50), size: (x: 100, y: 100, z: 100))
  var onCuboids = initHashSet[Cuboid]()
  for l in input:
    echo l
    let cop = l.parse
    echo cop
    if cop.isNone: continue
    let (op, cuboid) = cop.get
    if not bounds.contains cuboid: continue
    echo " ==> DOING"
    case op:
      of union: onCuboids += cuboid
      of difference: onCuboids -= cuboid
  echo onCuboids
  for c in onCuboids: result += (c.size.x * c.size.y * c.size.z).uint64
  # TODO: sum volume of all cuboids in `onCuboids`

proc p2(input: Lines): uint64 =
  0

const input = """
on x=-20..26,y=-36..17,z=-47..7
on x=-20..33,y=-21..23,z=-26..28
on x=-22..28,y=-29..23,z=-38..16
on x=-46..7,y=-6..46,z=-50..-1
on x=-49..1,y=-3..46,z=-24..28
on x=2..47,y=-22..22,z=-23..27
on x=-27..23,y=-28..26,z=-21..29
on x=-39..5,y=-6..47,z=-3..44
on x=-30..21,y=-8..43,z=-13..34
on x=-22..26,y=-27..20,z=-29..19
off x=-48..-32,y=26..41,z=-47..-37
on x=-12..35,y=6..50,z=-50..-2
off x=-48..-32,y=-32..-16,z=-15..-5
on x=-18..26,y=-33..15,z=-7..46
off x=-40..-22,y=-38..-28,z=23..41
on x=-16..35,y=-41..10,z=-47..6
off x=-32..-23,y=11..30,z=-14..3
on x=-49..-5,y=-3..45,z=-29..18
off x=18..30,y=-20..-8,z=-3..13
on x=-41..9,y=-7..43,z=-33..15
on x=-54112..-39298,y=-85059..-49293,z=-27449..7877
on x=967..23432,y=45373..81175,z=27513..53682
""".strip().split('\n')
doDayX 22, (n: int) => n.loadInput, p1, p2, (input, 590784'u64, 0'u64)