AoC2022-Day18-Part1.swift

import UIKit

var input =
"""
2,2,2
1,2,2
3,2,2
2,1,2
2,3,2
2,2,1
2,2,3
2,2,4
2,2,6
1,2,5
3,2,5
2,1,5
2,3,5
"""

let lines = input.split(whereSeparator: \.isNewline)

struct Cube: Equatable, Hashable {
    let x: Int
    let y: Int
    let z: Int
}

var cubes: Set<Cube> = []

for line in lines {
    let coords = line.split(separator: ",")
    cubes.insert(Cube(x: Int(String(coords[0]))!, y: Int(String(coords[1]))!, z: Int(String(coords[2]))!))
}

var surfaceArea = 0

for cube in cubes {
    let top = Cube(x: cube.x, y: cube.y + 1, z: cube.z)
    let bottom = Cube(x: cube.x, y: cube.y - 1, z: cube.z)
    let left = Cube(x: cube.x - 1, y: cube.y, z: cube.z)
    let right = Cube(x: cube.x + 1, y: cube.y, z: cube.z)
    let front = Cube(x: cube.x, y: cube.y, z: cube.z + 1)
    let back = Cube(x: cube.x, y: cube.y, z: cube.z - 1)
    let check: Set<Cube> = [top, bottom, left, right, front, back]
    let intersect = cubes.intersection(check)
    surfaceArea += (6 - intersect.count)
}

print(surfaceArea)