프로그래머스 - k진수에서 소수 개수 구하기

import Foundation

func isPrimeNumber(_ n: Int) -> Bool {
    if n == 1 {
        return false
    }
    for i in 2..<Int(sqrt(Double(n)) + 1) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func solution(_ n:Int, _ k:Int) -> Int {
    
    var converted = ""
    var tmp = n
    
    while tmp >= 1 {
        converted += String(tmp % k)
        tmp /= k
    }
    
    var convertedList = converted.reversed().map { String($0) }
    print(convertedList.joined())
    var answer = 0
    var savedValue = ""
    while !convertedList.isEmpty {
            if convertedList.last == "0" {
                convertedList.removeLast()
            } else {
                while let last = convertedList.last, last != "0" {
                    savedValue += String(convertedList.removeLast())
                }
                let reversedValue = savedValue.reversed().map { String($0) }.joined()
                if let number = Int(reversedValue), number > 1, isPrimeNumber(number) {
                    answer += 1
                }
                savedValue = ""
            }
        }
    
    
    return answer
}