在Kotlin中读入和打印回2d数组的最快方法？

import java.util.Scanner

fun main() {
    val scanner = Scanner(System.`in`)
    val n = scanner.nextInt() // 二维数组的行数
    val m = scanner.nextInt() // 二维数组的列数
    val arr = Array(n) { IntArray(m) }
    for (i in 0 until n) {
        for (j in 0 until m) {
            arr[i][j] = scanner.nextInt()
        }
    }
    scanner.close()
}

fun main() {
    val arr = arrayOf(
        intArrayOf(1, 2, 3),
        intArrayOf(4, 5, 6),
        intArrayOf(7, 8, 9)
    )
    for (row in arr) {
        for (element in row) {
            print("$element ")
        }
        println()
    }
}