프로그래머스 - 3진법 뒤집기

import Foundation

func solution(_ n: Int) -> Int {
    var tmp = n
    var list: [String] = []
    
    while tmp > 0 {
        list.append(String(tmp % 3))
        tmp /= 3
    }
    
    var result = 0
    for (i, char) in list.reversed().enumerated() {
        if let digit = Int(String(char)) {
            result += digit * Int(pow(Double(3), Double(i)))
        }
    }
    return result
}