LeetCode Merge k Sorted Lists

LeetCode解题之Merge k Sorted Lists

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原题

将k个有序的链表拼接成一个有序的链表。

注意点：

• Python中有自带的堆排序实现heapq

例子：

输入: lists = [[1->2>10],[3->9],[5->6]]
输出: 1->2->3->5->6->9->10

解题思路

整体思路与Merge Two Lists相同。不过就是从原来的两个数中取最小的节点改为从k个数中取最小的节点。这是一个典型的堆排序的应用，Python中堆排序可以用heapq实现。

AC源码

import heapq# Definition for singly-linked list.class ListNode(object):    def __init__(self, x):        self.val = x        self.next = Noneclass Solution(object):    def mergeKLists(self, lists):        """        :type lists: List[ListNode]        :rtype: ListNode        """        heap = []        for node in lists:            if node:                heapq.heappush(heap, (node.val, node))        temp = ListNode(-1)        head = temp        while heap:            smallestNode = heapq.heappop(heap)[1]            temp.next = smallestNode            temp = temp.next            if smallestNode.next:                heapq.heappush(heap, (smallestNode.next.val, smallestNode.next))        return head.next

欢迎查看我的Github (https://github.com/gavinfish/LeetCode-Python) 来获得相关源码。