HackerRank/Algorithm/QueueUsingTwoStacks kotlin

QueueUsingTwoStacks.kt

import java.util.*

const val QUEUE_ENQUEUE = 1
const val QUEUE_DEQUEUE = 2
const val QUEUE_PRINT_HEAD = 3

fun queueUsingTwoStacks(
    numberOfQueues: Int,
    scanner: Scanner = Scanner(System.`in`),
) {
    val queue = LinkedList<Int>()
    repeat(numberOfQueues) {
        val input = scanner.nextInt()
        when (input) {
            QUEUE_ENQUEUE -> {
                queue.add(scanner.nextInt())
            }

            QUEUE_DEQUEUE -> {
                queue.removeFirst()
            }

            QUEUE_PRINT_HEAD -> {
                println(queue.peek())
            }
        }
    }
}

fun main(args: Array<String>) {
    queueUsingTwoStacks(numberOfQueues = readln().toInt())
}