Merge pull request #1833 from Lustellz/main

[Lustellz] WEEK 04 solution

Author: Lustellz

merge-two-sorted-lists/Lustellz.ts

@@ -0,0 +1,25 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *     val: number
+ *     next: ListNode | null
+ *     constructor(val?: number, next?: ListNode | null) {
+ *         this.val = (val===undefined ? 0 : val)
+ *         this.next = (next===undefined ? null : next)
+ *     }
+ * }
+ */
+// runtime: 1ms
+// memory: 58.22MB
+
+function mergeTwoLists(list1: ListNode | null, list2: ListNode | null): ListNode | null {
+    // 1. if next exists
+    if(!list1 && !list2)
+    return null
+    else if(!list1) return list2
+    else if(!list2) return list1
+    // 2. compare value and link node
+    else if(list1.val <= list2.val) return new ListNode(list1.val, mergeTwoLists(list1.next, list2))
+    else return new ListNode(list2.val, mergeTwoLists(list1, list2.next))
+
+};