9th December solution - Advent of Code - swift

december09_1.swift

let preamble = 25

var solution1 = -1
for i in 0..<numbers.count {
    if !checkThatAnyNumbers(in: Array(numbers[i..<preamble + i]), sumTo: numbers[preamble + i]) {
        solution1 = numbers[preamble + i]
        break
    }
}

print(solution1)

func checkThatAnyNumbers(in numbers: [Int], sumTo sum: Int) -> Bool{
    for indexNum1 in 0..<numbers.count {
        for indexNum2 in (indexNum1 + 1)..<numbers.count {
            if numbers[indexNum1] + numbers[indexNum2] == sum {
                return true
            }
        }
    }
    return false
}

december09_2.swift

let newSum = solution1
var solution2 = [Int]()
outerLoop: for i in 0..<numbers.count {
    innerLoop: for i2 in (i + 1)..<numbers.count {
        let sum = numbers[i...i2].reduce(0, +)
        if sum > newSum {
            break innerLoop
        } else if sum == newSum {
            solution2 = Array(numbers[i...i2])
            break outerLoop
        }
    }
}
print(solution2.min()! + solution2.max()!)

december09_shared.swift

let filename = "/Users/felix/xCodeProjects/AdventOfCode2020.playground/Resources/december09.txt"
let contents = try! String(contentsOfFile: filename)
let lines = contents.components(separatedBy: CharacterSet.newlines)
let numbers = lines.compactMap { Int($0) }