23.js

/** ------------------------------------------------------------------------------
 * 
 * 23. Merge k Sorted Lists
 * Topics: Linked List
 * https://leetcode.com/problems/merge-k-sorted-lists/description/
 * 
 ------------------------------------------------------------------------------ */
/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode[]} lists
 * @return {ListNode}
 */
var mergeKLists = function (lists) {
  if (!lists || !lists.length) return null

  let arr = [],
    res = new ListNode(0)

  for (let i = 0; i < lists.length; i++) {
    let cur = lists[i]
    while (cur) {
      arr.push(cur.val)
      cur = cur.next
    }
  }
  console.log(arr)

  let cur = res

  arr
    .sort((a, b) => a - b)
    .forEach((n) => {
      let temp = new ListNode(n)
      cur.next = temp
      cur = cur.next
    })
  return res.next
}

console.log(
  mergeKLists([
    [1, 4, 5],
    [1, 3, 4],
    [2, 6],
  ]),
)