aoc2021/Sources/16/16.swift

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//
// File.swift
//
//
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// Created by Max Nuding on 15.12.21.
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//
import Foundation
import Runner
import Collections
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enum OperatorType: Int {
case sum = 0
case product = 1
case minimum = 2
case maximum = 3
case value = 4
case greaterThan = 5
case lessThan = 6
case equal = 7
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}
protocol Packet {
var version: Int { get }
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func getTotalVersion() -> Int
func getValue() -> Int
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}
struct ValuePacket: Packet {
let version: Int
let value: Int
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func getTotalVersion() -> Int { version }
func getValue() -> Int { value }
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}
struct OperatorPacket: Packet {
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let type: OperatorType
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let version: Int
let subPackets: [Packet]
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func getTotalVersion() -> Int { version + subPackets.map { $0.getTotalVersion() }.reduce(0, +) }
func getValue() -> Int {
let spValues = subPackets.map { $0.getValue() }
switch type {
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case .sum:
return spValues.reduce(0, +)
case .product:
return spValues.reduce(1, *)
case .minimum:
return spValues.min()!
case .maximum:
return spValues.max()!
case .greaterThan:
return spValues.first! > spValues.last! ? 1 : 0
case .lessThan:
return spValues.first! < spValues.last! ? 1 : 0
case .equal:
return spValues.first! == spValues.last! ? 1 : 0
case .value:
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fatalError()
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}
}
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}
class Day16: 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)
let bytes = parts.ToBinary().joined()
let packets = parsePacket(bytes: bytes)
let p: Packet = packets.0
print(p.getTotalVersion())
print(p.getValue())
}
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func parsePacket(bytes: String) -> (Packet, String) {
let version = bytes[bytes.startIndex..<bytes.index(bytes.startIndex, offsetBy: 3)].description.binaryToDecimal()
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let typeId = bytes[bytes.index(bytes.startIndex, offsetBy: 3)..<bytes.index(bytes.startIndex, offsetBy: 6)].description.binaryToDecimal()
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var value: Packet
var reminder: String
switch typeId {
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case 4:
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let (v, r) = parseLiteralPacketValue(bytes: bytes)
value = ValuePacket(version: version, value: v)
reminder = r
default:
let (v, r) = parseOperatorPacker(bytes: bytes)
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value = OperatorPacket(type: OperatorType(rawValue: typeId)!, version: version, subPackets: v)
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reminder = r
}
return (value, reminder)
}
func parseOperatorPacker(bytes: String) -> ([Packet], String) {
let startNextBitsIndex = bytes.index(bytes.startIndex, offsetBy: 7)
let lengthTypeId = bytes[bytes.index(bytes.startIndex, offsetBy: 6)..<startNextBitsIndex].description
let isTotalLength = lengthTypeId == "0"
let nextBitsLength = isTotalLength ? 15 : 11
let endNextBitsIndex = bytes.index(startNextBitsIndex, offsetBy: nextBitsLength)
let nextBits = bytes[startNextBitsIndex..<endNextBitsIndex].description
var number = nextBits.binaryToDecimal()
var reminder = bytes[endNextBitsIndex...].description
var subPackets = [Packet]()
while number > 0 {
let (p, rem) = parsePacket(bytes: reminder)
number -= isTotalLength ? (reminder.count - rem.count) : 1
subPackets.append(p)
reminder = rem
}
return (subPackets, reminder)
}
func parseLiteralPacketValue(bytes: String) -> (Int, String) {
var index = bytes.index(bytes.startIndex, offsetBy: 6)
var ei = index
var bits = ""
var reminder = ""
while true {
let si = bytes.index(index, offsetBy: 1)
ei = bytes.index(si, offsetBy: 4)
bits += bytes[si..<ei].description
if bytes[index] == "0" {
reminder = bytes[ei...].description
break
}
index = bytes.index(ei, offsetBy: 0)
}
return (bits.binaryToDecimal(), reminder)
}
}
extension String {
func ToBinary() -> [String] {
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self.map { $0.bits }
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}
func binaryToDecimal() -> Int {
self.reversed().enumerated().reduce(0, { p, cur in
p + (cur.element == "0" ? 0 : Int(pow(2.0, Double(cur.offset))))
})
}
}
extension Character {
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var bits: String {
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switch self {
case "0":
return "0000"
case "1":
return "0001"
case "2":
return "0010"
case "3":
return "0011"
case "4":
return "0100"
case "5":
return "0101"
case "6":
return "0110"
case "7":
return "0111"
case "8":
return "1000"
case "9":
return "1001"
case "A":
return "1010"
case "B":
return "1011"
case "C":
return "1100"
case "D":
return "1101"
case "E":
return "1110"
case "F":
return "1111"
default:
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fatalError()
}
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}
}