feat: add MergeTwoSortedLinkedLIsts algorithms

Data-Structures/Linked-List/MergeTwoSortedLinkedLists.js

@@ -0,0 +1,45 @@
+import { LinkedList } from './SinglyLinkedList.js'
+/**
+ * A LinkedList-based solution for merging two sorted linked lists into one sorted list.
+ *
+ * @param {LinkedList} list1 - The the first sorted linked list.
+ * @param {LinkedList} list2 - The second sorted linked list.
+ * @returns {LinkedList} - The merged sorted linked list.
+ *
+ * @example
+ * const list1 = new LinkedList([1,2,4]);
+ *
+ * const list2 = new LinkedList([1,3,4]);
+ *
+ * const result = mergeLinkedLists(list1, list2);
+ * // Returns the merged linked list representing 1 -> 1 -> 2 -> 3 -> 4 -> 4
+ */
+
+function mergeLinkedLists(list1, list2) {
+ const mergedList = new LinkedList()
+
+ let current1 = list1.headNode
+ let current2 = list2.headNode
+
+ while (current1 || current2) {
+ if (!current1) {
+ mergedList.addLast(current2.data)
+ current2 = current2.next
+ } else if (!current2) {
+ mergedList.addLast(current1.data)
+ current1 = current1.next
+ } else {
+ if (current1.data < current2.data) {
+ mergedList.addLast(current1.data)
+ current1 = current1.next
+ } else {
+ mergedList.addLast(current2.data)
+ current2 = current2.next
+ }
+ }
+ }
+
+ return mergedList
+}
+
+export { mergeLinkedLists }

Data-Structures/Linked-List/test/MergeTwoSortedLinkedLists.test.js

@@ -0,0 +1,39 @@
+import { expect } from 'vitest'
+import { mergeLinkedLists } from '../MergeTwoSortedLinkedLists.js'
+import { LinkedList } from '../SinglyLinkedList.js'
+
+describe('MergeTwoSortedLinkedLists', () => {
+ it('Merges two sorted linked lists', () => {
+ const list1 = new LinkedList([1, 2, 4])
+
+ const list2 = new LinkedList([1, 3, 4])
+
+ const expectedResult = new LinkedList([1, 1, 2, 3, 4, 4])
+
+ const result = mergeLinkedLists(list1, list2)
+
+ expect(result).toEqual(expectedResult)
+ })
+
+ it('Merges two empty linked lists', () => {
+ const list1 = new LinkedList()
+ const list2 = new LinkedList()
+
+ const expectedResult = new LinkedList()
+
+ const result = mergeLinkedLists(list1, list2)
+
+ expect(result).toEqual(expectedResult)
+ })
+
+ it('Merges one empty linked list with a non-empty one', () => {
+ const list1 = new LinkedList()
+ const list2 = new LinkedList([1])
+
+ const expectedResult = new LinkedList([1])
+
+ const result = mergeLinkedLists(list1, list2)
+
+ expect(result).toEqual(expectedResult)
+ })
+})