add: 合并两个有序链表

test/list/merge-two-sorted-lists.test.js

@@ -0,0 +1,23 @@
+import { mergeTwoLists } from '../../src/list/merge-two-sorted-lists'
+
+function ListNode (val) {
+  this.val = val
+  this.next = null
+}
+
+const arrToList = (arr) => {
+  const head = new ListNode(arr[0])
+  let current = head
+  for (let n = 1, len = arr.length; n < len; n++) {
+    current.next = new ListNode(arr[n])
+    current = current.next
+  }
+
+  return head
+}
+
+test('合并两个有序链表', () => {
+  expect(mergeTwoLists(arrToList([1, 2, 4]), arrToList([1, 3, 4]))).toEqual(arrToList([1, 1, 2, 3, 4, 4]))
+  expect(mergeTwoLists(arrToList([null]), arrToList([0, 3, 3, null]))).toEqual(arrToList([0, 3, 3, null]))
+  expect(mergeTwoLists(arrToList([1, 3, 8, 11, 15, null]), arrToList([2, null]))).toEqual(arrToList([1, 2, 3, 8, 11, 15, null]))
+})