51 lines
1.6 KiB
Swift
51 lines
1.6 KiB
Swift
import Foundation
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struct Machine {
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let (aX, aY): (Int, Int)
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let (bX, bY): (Int, Int)
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let (przX, przY): (Int, Int)
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func solve() -> Int? {
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let d = aX*bY - aY*bX
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let (a, ar) = (przX*bY - przY*bX).quotientAndRemainder(dividingBy: d)
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let (b, br) = (przY*aX - przX*aY).quotientAndRemainder(dividingBy: d)
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if ar == 0 && br == 0 {
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return a*3 + b
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}
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return nil
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}
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}
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func readInput(_ filePath: String) throws -> [Machine] {
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let btnA = try Regex(#"Button A: X\+([0-9]+), Y\+([0-9]+)"#)
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let btnB = try Regex(#"Button B: X\+([0-9]+), Y\+([0-9]+)"#)
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let prize = try Regex(#"Prize: X=([0-9]+), Y=([0-9]+)"#)
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let content = try String(contentsOfFile: filePath, encoding: .ascii)
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var machines: [Machine] = []
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var (aX, aY, bX, bY): (Int, Int, Int, Int) = (-1, -1, -1, -1)
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content.split(separator: "\n").forEach { line in
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if let m = line.wholeMatch(of: btnA) {
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aX = Int(m.output[1].substring!)!
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aY = Int(m.output[2].substring!)!
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} else if let m = line.wholeMatch(of: btnB) {
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bX = Int(m.output[1].substring!)!
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bY = Int(m.output[2].substring!)!
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} else if let m = line.wholeMatch(of: prize) {
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machines.append(Machine(aX: aX, aY: aY, bX: bX, bY: bY,
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przX: Int(m.output[1].substring!)!,
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przY: Int(m.output[2].substring!)!
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))
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}
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}
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return machines
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}
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let machines = try readInput(CommandLine.arguments[1])
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var answer = 0
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machines.forEach { m in
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print(m)
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if let cost = m.solve() { answer += cost }
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}
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print(answer)
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