Added 2022 day 25 solutions

TyShkan · Dec 26, 2022 · a82f64c · a82f64c
1 parent 52b1d02
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diff --git a/2022/Sources/2022/Day25.swift b/2022/Sources/2022/Day25.swift
@@ -0,0 +1,104 @@
+import Algorithms
+import Collections
+import Foundation
+import RegexBuilder
+
+enum Snafu: Character {
+	case minusTwo = "="
+	case minusOne = "-"
+	case zero = "0"
+	case one = "1"
+	case two = "2"
+
+	var decimal: Int {
+		switch self {
+		case .minusTwo: return -2
+		case .minusOne: return -1
+		case .zero: return 0
+		case .one: return 1
+		case .two: return 2
+		}
+	}
+
+	init?(decimal: Int) {
+		switch decimal {
+		case -2: self = .minusTwo
+		case -1: self = .minusOne
+		case 0: self = .zero
+		case 1: self = .one
+		case 2: self = .two
+		default: return nil
+		}
+	}
+}
+
+extension Int {
+	func snafu() -> [Snafu] {
+		var places: [Int: Int] = [:]
+		var place = 0
+		var copy = self
+		while copy != 0 {
+			places[place] = copy.quotientAndRemainder(dividingBy: 5).remainder
+			copy /= 5
+			place += 1
+		}
+
+		let validDigits = -2 ... 2
+		while places.values.contains(where: { validDigits.contains($0) == false }) {
+			for (place, value) in places.sorted(by: { $0.key > $1.key }) {
+				if validDigits.contains(value) {
+					continue
+				}
+
+				if value == 3 {
+					places[place] = -2
+					places[place + 1, default: 0] += 1
+				} else if value == 4 {
+					places[place] = -1
+					places[place + 1, default: 0] += 1
+				} else {
+					fatalError("Unexpected value, \(value)")
+				}
+			}
+		}
+
+		return places
+			.sorted(by: { $0.key > $1.key })
+			.map(\.value)
+			.map { Snafu(decimal: $0)! }
+	}
+}
+
+struct Day25: Day {
+	var input: String
+
+	init(input: String) {
+		self.input = input
+	}
+
+	func partOne() -> String {
+		input
+			.split(separator: "\n")
+			.map(parseLine)
+			.reduce(0, +)
+			.snafu()
+			.map(\.rawValue)
+			.map(String.init)
+			.joined()
+			.description
+	}
+
+	func partTwo() -> String {
+		"And We’re Done"
+	}
+
+	func parseLine(_ line: some StringProtocol) -> Int {
+		var result = 0
+		var multiplier = 1
+		for snafu in line.map({ Snafu(rawValue: $0)! }).reversed() {
+			result += multiplier * snafu.decimal
+			multiplier *= 5
+		}
+		return result
+	}
+}
diff --git a/2022/Sources/2022/main.swift b/2022/Sources/2022/main.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-typealias CurrentDay = Day24
+typealias CurrentDay = Day25
 
 let testInput = """
 <Insert your test input here>