描述

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.

Example:

Input:
[1->4->5,1->3->4,2->6
]
Output: 1->1->2->3->4->4->5->6

思路

借鉴Merge Two Sorted Lists的解决思路，对两个数组先进行排序，然后两两组合，排成一个序列。

将此视为一种迭代的分而治之的解决方案。

mergeTwoLists方法是一种递归的合并两个序列的方法

注意：

尽量不用erase方法，太耗时。

一些优化以避免vector.erase()

比如下述：

 while(lists.size() > 1){lists.push_back(mergeTwoLists(lists[0], lists[1]));lists.erase(lists.begin());lists.erase(lists.begin());}return lists.front();

改为使用指针方法遍历vector，最后取vector.back()

最终解决方案：

/*** Definition for singly-linked list.* struct ListNode {*     int val;*     ListNode *next;*     ListNode(int x) : val(x), next(NULL) {}* };*/
class Solution {
public:ListNode* mergeKLists(vector<ListNode*>& lists) {if(lists.empty()){return nullptr;}if(lists.size() == 1) return lists[0];int i = 0;while(i < lists.size() - 1){lists.push_back(mergeTwoLists(lists[i], lists[i+1]));i += 2;}return lists.back();}ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {if(l1 == nullptr){return l2;}if(l2 == nullptr){return l1;}if(l1->val <= l2->val){l1->next = mergeTwoLists(l1->next, l2);return l1;}else{l2->next = mergeTwoLists(l1, l2->next);return l2;}}
};

转载于:https://www.cnblogs.com/ygh1229/p/9718627.html

【LeetCode】【数组归并】Merge k Sorted Lists相关推荐

Python 解LeetCode：23. Merge k Sorted Lists
题目描述:把k个排序的链表组成的列表合并成一个排序的链表思路: 使用堆排序,遍历列表,把每个列表中链表的头指针的值和头指针本身作为一个元素放在堆中: 第一步中遍历完列表后,此时堆中最多会有n个元素, ...
LeetCode 之 JavaScript 解答第23题 —— 合并K个有序链表（Merge K Sorted Lists）
Time:2019/4/10 Title: Merge K Sorted Lists Difficulty: Difficulty Author: 小鹿题目:Merge K Sorted Lists ...
71. Merge k Sorted Lists
Merge k Sorted Lists Merge k sorted linked lists and return it as one sorted list. Analyze and descr ...
LeetCode算法入门- Merge Two Sorted Lists -day15
LeetCode算法入门- Merge Two Sorted Lists -day15 题目描述: Merge two sorted linked lists and return it as a n ...
21.Merge Two Sorted Lists 、23. Merge k Sorted Lists
21.Merge Two Sorted Lists 初始化一个指针作为开头,然后返回这个指针的next class Solution { public:ListNode* mergeTwoLists( ...
Merge k Sorted Lists leetcode java
题目: Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexit ...
[leetcode] Merge k Sorted Lists
2019独角兽企业重金招聘Python工程师标准>>> Merge k sorted linked lists and return it as one sorted list. A ...
[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. E ...
合并k个有序链表 python_[LeetCode] 23. 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. E ...

【LeetCode】【数组归并】Merge k Sorted Lists

描述

思路

注意：

【LeetCode】【数组归并】Merge k Sorted Lists相关推荐

最新文章

热门文章