方法1:将链表所有元素插入数组，直接对数组排序，再返回有序列表

复杂度与快排相同

class Solution:
    def mergeKLists(self , lists: List[ListNode]) -> ListNode:
        # write code here
        data_list = []
        for head in lists:
            cur = head
            while cur:
                data_list.append(cur.val)
                cur = cur.next
        data_list.sort()
        N0 = ListNode(-1)
        tmp = N0
        for v in data_list:
            tmp.next = ListNode(v)
            tmp = tmp.next
        return N0.next