[Swift] [1차] 캐시

func solution(_ cacheSize:Int, _ cities:[String]) -> Int {
    
    var time = 0
    var cache = [String]()
    var cities = cities.map { $0.lowercased() }
    
    for city in cities {
        if cache.contains(city) {
            time += 1
            cache.remove(at: cache.firstIndex(of: city)!)
            cache.append(city)
        } else {
            time += 5
            cache.append(city)
            if cache.count > cacheSize {
                cache.removeFirst()
            }
        }
    }

    return time
}