leetcode23

 public class Solution
     {
         public ListNode MergeKLists(ListNode[] lists)
         {
             var ary = new List<int>();
             for (var i = ; i < lists.Length; i++)
             {
                 var l = lists[i];
                 while (l != null)
                 {
                     ary.Add(l.val);
                     l = l.next;
                 }
             }
             ary = ary.OrderBy(x => x).ToList();
             ListNode tail = null;
             for (var i = ary.Count - ; i >= ;i--)
             {
                 var head = new ListNode(ary[i]);
                 head.next = tail;
                 tail = head;
             }
             return tail;
         }
     }

投机取巧的办法，时间复杂度还可以，空间占用比较多。