Question

题目内容

解题思路

创建新节点。

代码实现

/**
 * 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)
 *     }
 * }
 */

const mergeTwoLists = (
  list1: ListNode | null,
  list2: ListNode | null
): ListNode | null => {
  const head: ListNode = new ListNode(-1);
  let current: ListNode = head;
  while (list1 !== null && list2 !== null) {
    if (list1.val < list2.val) {
      current.next = list1;
      list1 = list1.next;
    } else {
      current.next = list2;
      list2 = list2.next;
    }
    current = current.next;
  }
  if (list1 === null) current.next = list2;
  if (list2 === null) current.next = list1;
  return head.next;
};