Merge Two Sorted Lists

Author: casentino

merge-two-sorted-lists/casentino.ts

@@ -0,0 +1,40 @@
+/**
+ * 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)
+ *     }
+ * }
+ */
+
+function mergeTwoLists(list1: ListNode | null, list2: ListNode | null): ListNode | null {
+  if (!list1 || !list2) {
+    return list1 ?? list2;
+  }
+  function merge(node1: ListNode | null, node2: ListNode | null) {
+    if (!node1 || !node2) {
+      return node1 ?? node2;
+    }
+    if (node1.val < node2.val) {
+      node1.next = merge(node1.next, node2);
+    }
+    if (node1.val >= node2.val) {
+      node2.next = merge(node1, node2.next);
+    }
+
+    return node1.val < node2.val ? node1 : node2;
+  }
+  return merge(list1, list2);
+}
+
+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;
+  }
+}