一.题目说明 这个题目是23. Merge k Sorted Lists,归并k个有序列表生成一个列表.难度为Hard,实际上并不难,我一次提交就对了. 二.我的解答 就是k路归并,思路很简单,实现也不难. #include<iostream> #include<vector> using namespace std; struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(NULL) {}…
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 这道题最简单的方法就是我们将K个链表中的所有数据都存进数组中,然后对数据进行…
题目 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 分析 合并k个有序链表. 我们从数据结构的链表章节学会了如何合并两个链表,针对此题,一个简单的解法便是遍历k次,两个链表合并,合并后的结果与下一个链表合并: 此时时间复杂度为O(nk),遗憾,提交会出现TLE. 所以,必须另觅他法,我们知道排序领域中很多方法都可以提高性能比如合并排序性能为O(n…
1.题目 21. 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. Example: Input: 1->2->4, 1->3->4 Output: 1->1->2->3->4-&g…
一.题目说明 这个题目是21. Merge Two Sorted Lists,归并2个已排序的列表.难度是Easy! 二.我的解答 既然是简单的题目,应该一次搞定.确实1次就搞定了,但是性能太差: Runtime: 20 ms, faster than 8.74% of C++ online submissions for Merge Two Sorted Lists. Memory Usage: 9.4 MB, less than 5.74% of C++ online submissions…
Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. 题解:开始想到的方法比较偷懒,直接遍历一遍数组,把每个ListNode对应的值放到数组里面,然后把数组转换成BST,想来这个题的本意肯定不是这样. 自己也想到了bottom-up的方法,但是没想明白怎么个bottom-up法,真的是昨天做梦都在想=.= 今天早上终于弄懂了,用递归…
Given an array where elements are sorted in ascending order, convert it to a height balanced BST. 题解:递归就可以了. Java代码如下: /** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val =…
Merge k Sorted Lists Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 题目意思: 合并K条已经排序的链表.分析时间复杂度. 解题思路: 很容易就想起之前学的合并两条链表的算法,这一题其实就是那个题目的扩展,变成合并K条了.我采用的方法就是迭代法. 如果只有一条,直接返回.如果只有两条,就只需要调用mergeTwo一下.如果超过两…
# -*- 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…
题目 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 翻译 合并k个有序的链表 Hints Related Topics: LinkedList, Divide and Conquer, Heap Solution1:Divide and Conquer 参考 归并排序-维基百科 思路:分治,先分成两个子任务,然后递归子任务,最后回溯回来..这里就…