(...as I still learning Kotlin) I found this problem:You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)Output: 7 -> 0 -> 8This is my solution so far:fun add(a: IntArray, b: IntArray): Iterable<Int> {  val result: MutableList<Int> = mutableListOf()  var remainder = 0  for (i in 0..Math.max(a.size, b.size) - 1) {    val sum = a.elementAtOrElse(i, { 0 }) + b.elementAtOrElse(i, { 0 }) + remainder    remainder = if (sum >= 10) 1 else 0    result.add(if (remainder >= 1) sum - 10 else sum)  }  if (remainder > 0) result.add(remainder)  return result}...test cases:import org.assertj.core.api.Assertions.assertThatimport org.junit.Testclass AddTwoNumbersTest {  @Test  fun test_Add() {    assertThat(add(intArrayOf(9, 6, 9, 5, 9), intArrayOf(1, 5, 1, 6, 1))).isEqualTo(listOf(0, 2, 1, 2, 1, 1))    assertThat(add(intArrayOf(4, 1, 8, 7, 2), intArrayOf(9, 4, 1, 0, 3))).isEqualTo(listOf(3, 6, 9, 7, 5))    assertThat(add(intArrayOf(2, 2, 3, 3), intArrayOf(4, 5, 6, 7))).isEqualTo(listOf(6, 7, 9, 0, 1))    assertThat(add(intArrayOf(4, 1, 0, 8), intArrayOf(2, 2, 7, 6))).isEqualTo(listOf(6, 3, 7, 4, 1))    assertThat(add(intArrayOf(2, 7, 1, 0), intArrayOf(0, 0, 8, 1))).isEqualTo(listOf(2, 7, 9, 1))    assertThat(add(intArrayOf(9, 9, 9), intArrayOf(9, 9, 9))).isEqualTo(listOf(8, 9, 9, 1))    assertThat(add(intArrayOf(9, 3, 7), intArrayOf(8, 7, 8))).isEqualTo(listOf(7, 1, 6, 1))    assertThat(add(intArrayOf(6, 6, 6), intArrayOf(7, 8, 9))).isEqualTo(listOf(3, 5, 6, 1))    assertThat(add(intArrayOf(0, 0, 0), intArrayOf(0, 0, 0))).isEqualTo(listOf(0, 0, 0))    assertThat(add(intArrayOf(2, 4, 3), intArrayOf(5, 6, 4))).isEqualTo(listOf(7, 0, 8))    assertThat(add(intArrayOf(0, 1), intArrayOf(0, 1, 2))).isEqualTo(listOf(0, 2, 2))    assertThat(add(intArrayOf(4, 6), intArrayOf(6, 4))).isEqualTo(listOf(0, 1, 1))    assertThat(add(intArrayOf(1), intArrayOf(9, 9))).isEqualTo(listOf(0, 0, 1))    assertThat(add(intArrayOf(), intArrayOf(0, 1))).isEqualTo(listOf(0, 1))    assertThat(add(intArrayOf(), intArrayOf())).isEmpty()  }}It works so far...so I'm wondering if you can improve this one, or have a better approach. Notice I use everything the language offer.
LeetCode: Add Two Numbers (in Kotlin)
programming challenge;kotlin
Using add as a function name seems very ambiguous. The method name used in the Java Solution class from LeetCode seems more appropriate: addTwoNumbers (thereby specifying that the arguments, although not numbers themselves, represent numbers).You can remove the explicit type specification for var result if you add explicit type arguments to mutableListOf(). I personally find this more readable and less verbose:var result = mutableListOf<Int>()You can use start until endExclusive instead of start..endInclusive - 1:for (i in 0 until Math.max(a.size, b.size))You can use the slightly shorter getOrElse instead of elementAtOrElse. You can also move trailing lambda arguments out of parentheses:val sum = a.getOrElse(i) { 0 } + b.getOrElse(i) { 0 } + remainderYou can use an overloaded operator for adding elements to a mutable list:result += if (remainder >= 1) sum - 10 else sumI wouldn't use remainder >= 1 or remainder > 0 because it makes it appear that remainder can be greater than 1 which is not true. I recommend using remainder == 1.Altogether:fun addTwoNumbers(a: IntArray, b: IntArray): Iterable<Int> {    val result = mutableListOf<Int>()    var remainder = 0    for (i in 0 until Math.max(a.size, b.size)) {        val sum = a.getOrElse(i) { 0 } + b.getOrElse(i) { 0 } + remainder        remainder = if (sum >= 10) 1 else 0        result += if (remainder == 1) sum - 10 else sum    }    if (remainder == 1) result.add(1)    return result}However, the problem specified in LeetCode does not use arrays which are very different from linked lists. If you convert the Java code it provides you would get the following:/** * Definition for singly-linked list. * class ListNode internal constructor(internal var `val`: Int) { *     internal var next: ListNode? = null * } */class Solution {    fun addTwoNumbers(l1: ListNode, l2: ListNode): ListNode {    }}Solving such a problem should result in a very different solution than what you've arrived at.