aoc2021/Sources/17/17.swift
2021-12-17 06:48:02 +01:00

108 lines
2.8 KiB
Swift

//
// File.swift
//
//
// Created by Max Nuding on 17.12.21.
//
import Foundation
import Runner
import Collections
struct Point:Hashable {
let x: Int
let y: Int
}
struct Area {
let topLeft: Point
let botRight: Point
init(x: String, y: String) {
let xVals = x[x.index(x.startIndex, offsetBy: 2)...].components(separatedBy: "..").map { Int($0)! }
let yVals = y[y.index(y.startIndex, offsetBy: 2)...].components(separatedBy: "..").map { Int($0)! }
topLeft = Point(x: xVals.first!, y: yVals.last!)
botRight = Point(x: xVals.last!, y: yVals.first!)
}
func contains(point: Point) -> Bool {
point.x >= topLeft.x && point.x <= botRight.x && point.y <= topLeft.y && point.y >= botRight.y
}
func overshot(point: Point) -> Bool {
overshotX(point: point) || overshotY(point: point)
}
func overshotX(point: Point) -> Bool {
point.x > botRight.x
}
func overshotY(point: Point) -> Bool {
point.y < botRight.y
}
}
struct Probe {
var position: Point
var velocity: Point
mutating func move() {
position = Point(x: position.x + velocity.x, y: position.y + velocity.y)
var dX: Int
switch velocity.x {
case _ where velocity.x < 0:
dX = 1
case 0:
dX = 0
case _ where velocity.x > 0:
dX = -1
default:
fatalError()
}
velocity = Point(x: velocity.x + dX, y: velocity.y - 1)
}
}
class Day17: Runnable {
let inputPath: String
required init(inputPath: String) {
self.inputPath = inputPath
}
public func run() {
let input = try! String(contentsOfFile: inputPath)
let parts = input
.trimmingCharacters(in: .newlines)
.components(separatedBy: ": ")
.last!
.components(separatedBy: ", ")
let area = Area(x: parts.first!, y: parts.last!)
var maxY = Int.min
var found = Set<Point>()
for x in -500...500 {
for y in -500...500 {
let velocity = Point(x: x, y: y)
var probe = Probe(position: Point(x: 0, y: 0), velocity: velocity)
var maxYCurrent = Int.min
while !area.contains(point: probe.position) && !area.overshot(point: probe.position) {
probe.move()
if probe.position.y > maxYCurrent {
maxYCurrent = probe.position.y
}
}
if area.contains(point: probe.position) {
if maxYCurrent > maxY {
maxY = maxYCurrent
}
found.insert(velocity)
}
}
}
print(maxY)
print(found.count)
}
}