From e70e71b0685a9f64294b74a0a78587e4651719ae Mon Sep 17 00:00:00 2001
From: Max Nuding <max.nuding@icloud.com>
Date: Thu, 16 Dec 2021 07:52:35 +0100
Subject: [PATCH] 16a

---
 Package.swift                              |  11 +-
 Sources/16/16.swift                        | 184 +++++++++++++++++++++
 Sources/16/main.swift                      |  12 ++
 Sources/Runner/Resources/input/16.txt      |   1 +
 Sources/Runner/Resources/input/16_test.txt |   1 +
 5 files changed, 206 insertions(+), 3 deletions(-)
 create mode 100644 Sources/16/16.swift
 create mode 100644 Sources/16/main.swift
 create mode 100644 Sources/Runner/Resources/input/16.txt
 create mode 100644 Sources/Runner/Resources/input/16_test.txt

diff --git a/Package.swift b/Package.swift
index caf8c54..046f1cb 100644
--- a/Package.swift
+++ b/Package.swift
@@ -24,7 +24,8 @@ let package = Package(
             .executable(name: "12", targets: ["12"]),
             .executable(name: "13", targets: ["13"]),
             .executable(name: "14", targets: ["14"]),
-            .executable(name: "15", targets: ["15"])
+            .executable(name: "15", targets: ["15"]),
+            .executable(name: "16", targets: ["16"])
         ],
     dependencies: [
         // Dependencies declare other packages that this package depends on.
@@ -112,12 +113,16 @@ let package = Package(
         .executableTarget(
             name: "14",
             dependencies: [ .targetItem(name: "Runner", condition: nil) ]
-        )
-        ,
+        ),
         .executableTarget(
             name: "15",
             dependencies: [ .targetItem(name: "Runner", condition: nil),
                             .product(name: "Collections", package: "swift-collections")]
+        ),
+        .executableTarget(
+            name: "16",
+            dependencies: [ .targetItem(name: "Runner", condition: nil),
+                            .product(name: "Collections", package: "swift-collections")]
         )
     ]
 )
diff --git a/Sources/16/16.swift b/Sources/16/16.swift
new file mode 100644
index 0000000..19113f7
--- /dev/null
+++ b/Sources/16/16.swift
@@ -0,0 +1,184 @@
+//
+//  File.swift
+//
+//
+//  Created by Max Nuding on 15s.12.21.
+//
+
+import Foundation
+import Runner
+import Collections
+
+enum PacketType: String {
+    case value
+    case op
+    
+    init(rawValue: String) {
+        switch rawValue {
+        case "100":
+            self = .value
+        default:
+            self = .op
+        }
+    }
+}
+
+protocol Packet {
+    //var type: PacketType { get }
+    var version: Int { get }
+}
+
+struct ValuePacket: Packet {
+    //let type: PacketType
+    let version: Int
+    let value: Int
+}
+
+struct OperatorPacket: Packet {
+    //let type: PacketType
+    let version: Int
+    let subPackets: [Packet]
+}
+
+class Day16: Runnable {
+    let inputPath: String
+    
+    required init(inputPath: String) {
+        self.inputPath = inputPath
+    }
+    
+    public func run() {
+        let input = try! String(contentsOfFile: inputPath)
+        //let input = "620080001611562C8802118E34"
+        //let input = "D2FE28"
+        let parts = input
+            .trimmingCharacters(in: .newlines)
+        let bytes = parts.ToBinary().joined()
+        let packets = parsePacket(bytes: bytes)
+        let p: Packet = packets.0
+        let totalVersion = getPacketVersion(p: p)
+        print(totalVersion)
+    }
+    
+    func getPacketVersion(p: Packet) -> Int {
+        //print("Found packet: \(p)")
+        if let packet = p as? OperatorPacket {
+            return packet.version + packet.subPackets.map(getPacketVersion).reduce(0, +)
+        } else {
+            return p.version
+        }
+    }
+    
+    func parsePacket(bytes: String) -> (Packet, String) {
+        let version = bytes[bytes.startIndex..<bytes.index(bytes.startIndex, offsetBy: 3)].description.binaryToDecimal()
+        let typeId = bytes[bytes.index(bytes.startIndex, offsetBy: 3)..<bytes.index(bytes.startIndex, offsetBy: 6)].description
+        var value: Packet
+        var reminder: String
+        switch typeId {
+        case "100":
+            let (v, r) = parseLiteralPacketValue(bytes: bytes)
+            value = ValuePacket(version: version, value: v)
+            reminder = r
+        //case "110":
+        //    break
+        default:
+            //fatalError("Unknown packet \(typeId)")
+            let (v, r) = parseOperatorPacker(bytes: bytes)
+            value = OperatorPacket(version: version, subPackets: v)
+            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] {
+        self.map {$0.toBinary()!}
+    }
+    
+    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 {
+    func toBinary() -> String? {
+        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:
+            return nil}
+    }
+}
diff --git a/Sources/16/main.swift b/Sources/16/main.swift
new file mode 100644
index 0000000..1a305a7
--- /dev/null
+++ b/Sources/16/main.swift
@@ -0,0 +1,12 @@
+//
+//  File.swift
+//  
+//
+//  Created by Max Nuding on 15.12.21.
+//
+
+import Foundation
+import Runner
+
+//Runner(target: Day16.self, day: "16", isTest: true).run()
+Runner(target: Day16.self, day: "16", isTest: false).run()
diff --git a/Sources/Runner/Resources/input/16.txt b/Sources/Runner/Resources/input/16.txt
new file mode 100644
index 0000000..53f5708
--- /dev/null
+++ b/Sources/Runner/Resources/input/16.txt
@@ -0,0 +1 @@
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
diff --git a/Sources/Runner/Resources/input/16_test.txt b/Sources/Runner/Resources/input/16_test.txt
new file mode 100644
index 0000000..a7f8f25
--- /dev/null
+++ b/Sources/Runner/Resources/input/16_test.txt
@@ -0,0 +1 @@
+38006F45291200