[HackerRank] Dynamic Array

/**
 * https://www.hackerrank.com/challenges/dynamic-array/problem
 * */
class DynamicArray {

    var lastAnswer = 0
    var answerList: ArrayList<Int>? = null
    var seqs: ArrayList<ArrayList<Int>>? = null

    fun dynamicArray(n: Int, queries: Array<Array<Int>>): Array<Int> {

        seqs = ArrayList<ArrayList<Int>>()
        for (i in 0 until n) {
            seqs!!.add(ArrayList<Int>())
        }

        answerList = ArrayList()

        val size = queries.size
        for (i in 0 until size) {
            val type = queries[i][0]
            val x = queries[i][1]
            val y = queries[i][2]
            val seqIndex = (x xor lastAnswer) % n

            when (type) {
                1 -> {
                    val list = seqs!!.get(seqIndex)
                    list.add(y)
                }
                2 -> {
                    val list = seqs!![seqIndex]
                    val index = y % list.size
                    lastAnswer = list.get(index)
                    answerList!!.add(lastAnswer)
                }
            }
        }

        val count = answerList!!.size
        val array = Array<Int>(count, { 0 })
        answerList!!.toArray(array)
        return array
    }
}