[leetcode]_Merge Two Sorted Lists

题目:合并两个有序单链表思路:一开始想复杂了,以为必须在原链表上修改(绕来绕去还AC了,但是思路相当绕),其实没有,按照正常地合并两个数组同样的方法也对. 代码: public ListNode mergeTwoLists(ListNode l1, ListNode l2) { if(l1 == null) return l2; else if(l2 == null) return l1; else{ ListNode p = new ListNode(0); ListNode head =…

[LeetCode] Merge k Sorted Lists 合并k个有序链表

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 这道题让我们合并k个有序链表,之前我们做过一道Merge Two Sorted Lists 混合插入有序链表,是混合插入两个有序链表.这道题增加了难度,变成合并k个有序链表了,但是不管合并几个,基本还是要两两合并.那么我们首先考虑的方法是能不能利用之前那道题的解法来解答此题.答案是肯定的,但是需要修改…

[LeetCode] Merge Two Sorted Lists 混合插入有序链表

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. 这道混合插入有序链表和我之前那篇混合插入有序数组非常的相似Merge Sorted Array,仅仅是数据结构由数组换成了链表而已,代码写起来反而更简洁.具体思想就是新建一个链表,然后比较两个链表中的元素值,把较小的…

LeetCode: Merge Two Sorted Lists 解题报告

Merge Two Sorted Lists Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. Show Tags SOLUTION 1: 使用dummynode记录头节点的前一个,轻松完成,2分钟就AC啦! /** * Definition for singly-…

LeetCode: Merge k Sorted Lists 解题报告

Merge k Sorted Lists Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Show Tags 参考资料: http://blog.csdn.net/linhuanmars/article/details/19899259. SOLUTION 1: 使用分治法.左右分别递归调用Merge K sorted List,然后再使用merg…

[Leetcode] Merge k sorted lists 合并k个已排序的链表

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 思路:这题最容易想到的是,(假设有k个链表)链表1.2合并,然后其结果12和3合并,以此类推,最后是123--k-1和k合并.至于两链表合并的过程见merge two sorted lists的分析.复杂度的分析见JustDoIT的博客.算法复杂度:假设每个链表的平均长度是n,则1.2合并,遍历2n个…

leetcode先刷_Merge Two Sorted Lists

非常easy问题. 唯一的地方可以具有更具挑战是确保不会引入额外的空间.查找开始值最小的名单列表的新掌门人,头从列表中删除.其他操作应该没有问题. class Solution { public: ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) { if(l1 == NULL) return l2; if(l2 == NULL) return l1; if(l1->val>l2->val) swap(l1, l2); ListNod…

LeetCode:Merge k Sorted Lists

题目链接 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 合并k个有序的链表,我们假设每个链表的平均长度是n.这一题需要用到合并两个有序的链表子过程算法1: 最傻的做法就是先1.2合并,12结果和3合并,123结果和4合并,…,123..k-1结果和k合并,我们计算一下复杂度. 1.2合并,遍历2n个节点 12结果和3合并,遍历3n个节点 123…

LeetCode——Merge k Sorted Lists

Discription: Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Subscribe to see which companies asked this question. 思路:其实就是归并排序的最后一步归并操作.思想是递归分治,先把一个大问题分成2个子问题,然后对2个子问题的解进行合并.经过一次遍历就能找出已经有序的序列.就算是题目中给…

leetcode:Merge Two Sorted Lists（有序链表的归并）

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. 分析:思路比较简单,遍历两个有序链表,每次指向最小值. code如下: /** * Definition for singly-linked list. * struct ListNode { * int val;…

leetcode -- Merge k Sorted Lists add code

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. [解题思路] 以前的解法的时间复杂度过高,通过在网上搜索,得到优化的时间复杂度:O(n*lgk) 维护一个大小为k的最小堆,每次得到一个最小值,重复n次 /** * Definition for singly-linked list. * public class ListNode { * int v…

LeetCode Merge k Sorted Lists 解决报告

https://oj.leetcode.com/problems/merge-k-sorted-lists/ 归并K已经整理阵列,和分析算法的复杂. 解决报告:无论是不考虑优化,最简单的实现是要重新走路List<ListNode>.对当中每一个链表同当前链表做一遍类似于归并排序最后一步的merge操作. 算法复杂度是O(KN) public class Solution { ListNode mergeTwoLists(ListNode list1, ListNode list2) { Lis…

LeetCode Merge k Sorted Lists (链表)

题意 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 将K个排好序的链表合并成一个解法和之前合并两个有序链表那题不同,那题用的是两个指针来分别记录两个链表中的位置,将小的那个插入新链表然后指针右移,有点像归并排序时用到的方法.这题如果用K个指针来记录的话,每次需要找出最小的那个值,比较麻烦,所以采用的优先队列,首先将所有链表的第一个值入队,然后…

[Leetcode] Merge two sorted lists 合并两已排序的链表

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. 题意:合并两个排好的链表并返回新的链表. 可以使用归并排序,从两链表的表头,取出结点,比较两值,将较小的放在新链表中.如1->3->5->6和2->4->7->8,先将1放入新链表,然后将3…

LeetCode OJ-- Merge k Sorted Lists *@

https://oj.leetcode.com/problems/merge-k-sorted-lists/ 这道题主要是考虑测试数据的特点吧. 刚开始的时候想,每次找出头结点中最小的两个,然后取最小的一个,一直取到它的值 > 倒数第二小的,之后重复这个过程. 适合的数据特点为: 1 2 3 5 6 7 10 20 11 12 15 18 …… 这样子的于是写出了代码,但是超时了. 超时的数据是这样的:[{7},{49},{73},{58},{30},{72},{44},{78},{23},{…

LeetCode OJ--Merge Two Sorted Lists

http://oj.leetcode.com/problems/merge-two-sorted-lists/ 有序链表的归并排序 #include <iostream> using namespace std; struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(NULL) {} }; class Solution { public: ListNode *mergeTwoLists(ListNod…

LeetCode —— Merge k Sorted Lists

/* ** 算法的思路: ** 1.将k个链表的首元素进行建堆 ** 2.从堆中取出最小的元素,放到链表中 ** 3.如果取出元素的有后续的元素,则放入堆中,若没有则转步骤2,直到堆为空 */ #include <stdio.h> struct ListNode { int val; struct ListNode *next; }; #define PARENT(i) (((i)-1)/2) #define LEFT(i) ((i)*2+1) #define RIGHT(i) ((i)*2+…

leetcode Merge K sorted Lists python

# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def mergeKLists(self, lists): """ :type lists: List[ListNode] :rtype: ListNode ""&qu…

Leetcode:Merge k Sorted Lists分析和实现

题目大意是传入一个链表数组lists,每个链表都由若干个链接的链表结点组成,并且每个链表结点记录一个整数.题目保证传入的链表中的整数按从小到大进行排序. 题目要求我们输出一个新的链表,这个链表中应该包含所有在lists中出现的整数,并且按从小到大排序. 我的思路: 这个问题解法应该很多.我采用的解法是分治算法,灵感来自于归并排序,因为归并排序的递归完成后也会涉及到将两个有序数组重组合并. 首先说明如何重组两个链表为一个有序链表,其思路源自于我们在玩扑克牌时对两堆有序扑克牌进行排序的手法: 1.我…

leetcode Merge Two Sorted Lists python

# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def mergeTwoLists(self, l1, l2): """ :type l1: ListNode :type l2: ListNode :rtype: ListNode &q…

LeetCode Merge Two Sorted Lists 归并排序

题意: 将两个有序的链表归并为一个有序的链表. 思路: 设合并后的链表为head,现每次要往head中加入一个元素,该元素要么属于L1,要么属于L2,可想而知,此元素只能是L1或者L2的首个元素,那么进行一次比较就可以知道是谁了.操作到L1或L2其中一个已经没有元素为止,剩下的直接加到head后面. /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListN…

Java for LeetCode 023 Merge k Sorted Lists

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 解题思路一: 之前我们有mergeTwoLists(ListNode l1, ListNode l2)方法,直接调用的话,需要k-1次调用,每次调用都需要产生一个ListNode[],空间开销很大.如果采用分治的思想,对相邻的两个ListNode进行mergeTwoLists,每次将规模减少一半,直到…

[Leetcode][Python]21: Merge Two Sorted Lists

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 21: Merge Two Sorted Listshttps://oj.leetcode.com/problems/merge-two-sorted-lists/ Merge two sorted linked lists and return it as a new list.The new list should be made by splicing together…

[Leetcode][Python]23: Merge k Sorted Lists

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 23: Merge k Sorted Listshttps://oj.leetcode.com/problems/merge-k-sorted-lists/ Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. ===Comments…

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