题解 | #合并k个已排序的链表#

import heapq
class ListNode:
     def __init__(self, x):
         self.val = x
         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param lists ListNode类一维数组 
# @return ListNode类
#
class Solution:
    def mergeKLists(self , lists: List[ListNode]):
        li=[]
        if not lists:
            return
        
        for node in lists:
                while node:
                        li.append(node.val)
                        node=node.next
        if li:
            heapq.heapify(li)#建小根堆
            root=ListNode(heapq.heappop(li))#构造链表，建立根节点
            cur=root#当前节点
            while li:
                    nextnode=ListNode(heapq.heappop(li))
                    cur.next=nextnode#把根节点与下一节点相连
                    cur=nextnode
            return root