Improved tasks 23, 47

Author: javadev

src/main/kotlin/g0001_0100/s0023_merge_k_sorted_lists/Solution.kt

@@ -16,13 +16,13 @@ import com_github_leetcode.ListNode
  * }
  */
 class Solution {
-    fun mergeKLists(lists: Array<ListNode>): ListNode? {
+    fun mergeKLists(lists: Array<ListNode?>): ListNode? {
         return if (lists.isEmpty()) {
             null
         } else mergeKLists(lists, 0, lists.size)
     }
 
-    private fun mergeKLists(lists: Array<ListNode>, leftIndex: Int, rightIndex: Int): ListNode? {
+    private fun mergeKLists(lists: Array<ListNode?>, leftIndex: Int, rightIndex: Int): ListNode? {
         return if (rightIndex > leftIndex + 1) {
             val mid = (leftIndex + rightIndex) / 2
             val left = mergeKLists(lists, leftIndex, mid)

src/main/kotlin/g0001_0100/s0047_permutations_ii/Solution.kt

@@ -4,7 +4,7 @@ package g0001_0100.s0047_permutations_ii
 // #2023_07_05_Time_199_ms_(100.00%)_Space_39.1_MB_(92.98%)
 
 class Solution {
-    private var ans: MutableList<List<Int>>? = null
+    private lateinit var ans: MutableList<List<Int>>
 
     fun permuteUnique(nums: IntArray): List<List<Int>> {
         ans = ArrayList()
@@ -18,7 +18,7 @@ class Solution {
             for (n in nums) {
                 t.add(n)
             }
-            ans!!.add(t)
+            ans.add(t)
             return
         }
         permute(nums, p + 1)