49 lines
1.6 KiB
Swift
49 lines
1.6 KiB
Swift
//
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// File.swift
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//
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//
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// Created by Max Nuding on 05.12.21.
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//
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import Foundation
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import Runner
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struct Day07: Runnable {
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let inputPath: String
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func run() {
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let input = try! String(contentsOfFile: inputPath)
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let horizontalPositions = input
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.trimmingCharacters(in: .newlines)
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.components(separatedBy: ",")
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.map { Int($0)! }
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runA(horizontalPositions: horizontalPositions)
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runB(horizontalPositions: horizontalPositions)
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}
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func runA(horizontalPositions: [Int]) {
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let median = horizontalPositions.sorted()[horizontalPositions.count / 2]
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let distancesToMedian = horizontalPositions.map { abs(median - $0) }
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let toalFuel = distancesToMedian.reduce(0,+)
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print(toalFuel)
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}
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func runB(horizontalPositions: [Int]) {
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let average = Double(horizontalPositions.reduce(0, +)) / Double(horizontalPositions.count)
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let roundedDown = Int(floor(average))
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let roundedUp = Int(ceil(average))
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let fuelForRoundedDown = fuelConsumptionFor(horizontalPositions: horizontalPositions, toPosition: roundedDown)
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let fuelForRoundedUp = fuelConsumptionFor(horizontalPositions: horizontalPositions, toPosition: roundedUp)
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print(min(fuelForRoundedDown, fuelForRoundedUp))
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}
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func fuelConsumptionFor(horizontalPositions: [Int], toPosition targetPos: Int) -> Int {
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horizontalPositions.map { fuelConsumptionFor(numSteps: abs(targetPos - $0)) }.reduce(0,+)
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}
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func fuelConsumptionFor(numSteps: Int) -> Int {
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let dv = Double(numSteps)
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return Int((pow(dv, 2) + dv) / 2.0)
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}
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}
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