큐[BOJ]

코드

import Foundation

struct Queue {
    private var list: [Int] = []

    mutating func push(value: Int) {
        list.append(value)
    }

    mutating func pop() -> Int{
        list.isEmpty ? -1 : list.removeFirst()
    }

    func size() -> Int {
        return list.count
    }

    func empty() -> Int {
        return list.isEmpty ? 1 : 0
    }

    func front() -> Int {
        return list.first ?? -1
    }

    func back() -> Int {
        return list.last ?? -1
    }
}


var queue = Queue()

for _ in 0..<Int(readLine()!)! {
    let commnad = readLine()!.split(separator: " ")
    switch commnad[0] {
    case "push":
        queue.push(value: Int(commnad[1])!)  
    case "front":
        print(queue.front())
    case "back":
        print(queue.back())
    case "size":
        print(queue.size())
    case "pop":
        print(queue.pop())
    case "empty":
        print(queue.empty())
    default:
        break
    }
}