leetcode23

public class Solution
    {
        public ListNode MergeKLists(ListNode[] lists)
        {
            var ary = new List<int>();
            for (var i = 0; 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 - 1; i >= 0;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。