Counting Sheep

counting-sheep.swift

import Foundation

struct Input {
    let numberTestCases: Int // Included in input, but not needed
    let testCases: [Int]
}

func inputFromStandardInput() -> Input {
    let standardInput = FileHandle.standardInput
    let input = standardInput.availableData
    let text = String(data: input, encoding: String.Encoding.utf8)!
    let array: [Int?] = text.components(separatedBy: CharacterSet.newlines).map({Int($0)})
    let filtered: [Int] = array.filter({$0 != nil}).map({$0!})
    return Input(numberTestCases: filtered[0], testCases: Array(filtered[1...filtered.count-1]))
}

func lastNumberBeforeFallingAsleepForValue(value: Int) -> Int? {
    guard value > 0 else { return nil }
    
    var tally = [
        0:0, 1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0, 8:0, 9:0
    ]
    
    var index = 1
    var lastNumber: Int? = nil
    while (tallyIsComplete(tally: tally) == false) {
        lastNumber = value * index
        index = index + 1
        tally = updatedTallyWithValue(value: lastNumber!, tally: tally)
    }
    
    return lastNumber
}

func updatedTallyWithValue(value: Int, tally: [Int: Int]) -> [Int: Int] {
    var updatedTally = tally
    for character in value.description.characters.map({ Int(String($0))! }) {
        updatedTally[character] = 1
    }
    return updatedTally
}

func tallyIsComplete(tally: [Int: Int]) -> Bool {
    return tally.filter{$0.value == 0}.count == 0
}

let input = inputFromStandardInput()
for (index, value) in input.testCases.enumerated() {
    let caseNumber = index + 1
    if let lastNumber = lastNumberBeforeFallingAsleepForValue(value: value) {
        print("Case #\(caseNumber): \(lastNumber)")
    } else {
        print("Case #\(caseNumber): INSOMNIA")
    }
}