aoc2021/Sources/01/01.swift

//
//  File.swift
//  
//
//  Created by Max Nuding on 01.12.21.
//

import Foundation
import Runner

struct Day01: Runnable {
    let inputPath: String
    
    
    func run() {
        let input = try! String(contentsOfFile: inputPath)
        let distances = input
            .components(separatedBy: .newlines)
            .compactMap { Int($0) }
        runA(distances: distances)
        runB(distances: distances)
    }
    func runA(distances: [Int]) {
        let measurements = distances.reduce((currentCount: 0, lastValue: Int.max)) { partialResult, currentValue in
            let increaseBy = currentValue > partialResult.lastValue ? 1 : 0
            return (currentCount: partialResult.currentCount + increaseBy, lastValue: currentValue)
        }
        print(measurements.currentCount)
    }
    
    func runB(distances: [Int]) {
        
        // Sliding window would've been better, but I was too tired to bend reduce to my will. Oh well!
        var arrA = [Int]()
        var arrB = [Int]()
        var arrC = [Int]()
        var sumA = Int.max
        var sumB = Int.max
        var sumC = Int.max
        var increases = 0
        
        for (idx, distance) in distances.enumerated() {
            arrA.append(distance)
            if idx == 0 {
                continue
            }
            arrB.append(distance)
            if idx == 1 {
                continue
            }
            arrC.append(distance)
            if arrA.count == 3 {
                sumA = arrA.reduce(0, +)
                arrA = [Int]()
                if sumA > sumC {
                    increases += 1
                }
            }
            if arrB.count == 3 {
                sumB = arrB.reduce(0, +)
                arrB = [Int]()
                if sumB > sumA {
                    increases += 1
                }
            }
            if arrC.count == 3 {
                sumC = arrC.reduce(0, +)
                arrC = [Int]()
                if sumC > sumB {
                    increases += 1
                }
            }
        }
        print(increases)
    }
}