03a

Sources/aoc2021/03.swift

@@ -0,0 +1,64 @@
+//
+//  File.swift
+//
+//
+//  Created by Max Nuding on 02.12.21.
+//
+
+import Foundation
+import AppKit
+
+struct Day03 {
+    let inputPath: String
+    
+    func run() {
+        let input = try! String(contentsOfFile: inputPath)
+        let commands = input
+            .components(separatedBy: .newlines)
+            .filter { !$0.isEmpty }
+            //.compactMap { MoveCommand(line: $0) }
+        runA(commands)
+        //runB(commands)
+    }
+    
+    func runA(_ commands: [String]) {
+        let neededForMajority = commands.count / 2
+        let lastBitIndex = commands.first!.count
+        var countsOnes = [Int](repeating: 0, count: lastBitIndex)
+        for command in commands {
+            let m = command.map { Bool.init(digit: $0)! }.map { $0 ? 1 : 0 }
+            countsOnes.enumerated().forEach { (idx, elem) in
+                countsOnes[idx] += m[idx]
+            }
+        }
+        let dec = countsOnes.indices.reduce((gamma: 0, episolon: 0), { partialResult, idx in
+            let isOne = countsOnes[idx] > neededForMajority
+            let val = Int(truncating: NSDecimalNumber(decimal: pow(2, countsOnes.count - idx - 1)))
+            var (gamma, episolon) = partialResult
+            if isOne {
+                gamma += val
+            } else {
+                episolon += val
+            }
+            return (gamma, episolon)
+        })
+        print(dec.episolon * dec.gamma)<
+    }
+    
+    func runB(_ commands: [String]) {
+        
+    }
+}
+
+extension Bool {
+    init?(digit: Character) {
+        switch digit {
+        case "0":
+            self = false
+        case "1":
+            self = true
+        default:
+            return nil
+        }
+    }
+}

Sources/aoc2021/main.swift

@@ -1,5 +1,5 @@
 import Foundation
-
+//import Collections
 /*
 print("Starting day 01")
 let input01 = Bundle.module.path(forResource: "01", ofType: ".txt")!
@@ -10,6 +10,7 @@ let execTimeMs = round((end - start) * 1000.0 * 100.0) / 100.0
 print("Finished in \(execTimeMs)ms")
 */
 
+/*
 print("Starting day 02")
 let input02 = Bundle.module.path(forResource: "02", ofType: ".txt")!
 let start = CFAbsoluteTimeGetCurrent()
@@ -17,3 +18,12 @@ Day02(inputPath: input02).run()
 let end = CFAbsoluteTimeGetCurrent()
 let execTimeMs = round((end - start) * 1000.0 * 100.0) / 100.0
 print("Finished in \(execTimeMs)ms")
+*/
+
+print("Starting day 03")
+let input03 = Bundle.module.path(forResource: "03", ofType: ".txt")!
+let start = CFAbsoluteTimeGetCurrent()
+Day03(inputPath: input03).run()
+let end = CFAbsoluteTimeGetCurrent()
+let execTimeMs = round((end - start) * 1000.0 * 100.0) / 100.0
+print("Finished in \(execTimeMs)ms")