solution of merge two sorted lists

Author: grapefruit13

merge-two-sorted-lists/grapefruit13.ts

@@ -0,0 +1,33 @@
+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;
+  }
+}
+
+/**
+ * Time Complexity: O(n + m)
+ * Space Complexity: O(1)
+ */
+function mergeTwoLists(
+  list1: ListNode | null,
+  list2: ListNode | null
+): ListNode | null {
+  const dummy = new ListNode(0);
+  let current = dummy;
+
+  while (list1 && list2) {
+    if (list1.val < list2.val) {
+      current.next = list1;
+      list1 = list1.next;
+    } else {
+      current.next = list2;
+      list2 = list2.next;
+    }
+    current = current.next;
+  }
+  current.next = list1 || list2;
+  return dummy.next;
+}