Merge sorted arrays

MergeSortedArraysTest.kt

import org.junit.Test
import java.util.*

class MergeArraySortTest {

    @Test
    fun test() {
        val original = LinkedList(mutableListOf(4, 5, 8, 11, 15, 17, 20)) //n
        val addition =
            LinkedList(mutableListOf(1, 3, 6, 10, 11, 13, 19, 21)) //m

        println(mergeSortedArrays(original, addition))
    }

    private fun mergeSortedArrays(original: LinkedList<Int>, addition: LinkedList<Int>): List<Int> {
        if (original.isEmpty()) {
            return addition
        }

        var j = 0
        for (i in 0 until addition.size) {
            when {
                addition[i] <= original.first() -> original.add(i, addition[i])
                addition[i] > original.last() -> original.add(addition[i])
                else -> {
                    for (k in j until original.size) {
                        if (addition[i] <= original[k]) {
                            original.add(k, addition[i])
                            j = k
                            break
                        }
                    }
                }
            }
        }
        return original
    }
}