Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

本题可以用reservoir sampling来解决不明list长度的情况下平均概率选择元素的问题. 假设在[x_1,...,x_n]只选一个元素,要求每个元素被选中的概率都是1/n,但是n未知. 其中 random.randint(0, cnt) == 0: 的概率是1/(cnt+1).reservoir sampling的证明可以使用归纳法(induction). class Solution(object): def __init__(self, head): """…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up:What if the linked list is extremely large and its length is unknown to you? Could you solve this effic…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up:What if the linked list is extremely large and its length is unknown to you? Could you solve this effic…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up:What if the linked list is extremely large and its length is unknown to you? Could you solve this effic…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up:What if the linked list is extremely large and its length is unknown to you? Could you solve this effic…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

Linked List & List Node All In One 链表 & 节点 链表类型 单链表 双链表 环形链表 / 循环链表 Singly Linked List (Uni-directional) Doubly Linked List (Bi-directional) Circular Linked List js 实现 Linked List "use strict"; /** * * @author xgqfrms * @license MIT * @c…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 数组保存再随机选择 蓄水池抽样 日期 题目地址:https://leetcode.com/problems/linked-list-random-node/description/ 题目描述 Given a singly linked list, return a random node's value from the linked list. E…

这题参照http://blog.jobbole.com/42550/ 用的蓄水池算法,即更改ans的概率为1/(当前length) /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ public class Solution { private ListNode head; /**…

otal Accepted: 48115 Total Submissions: 109291 Difficulty: Easy Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third…

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value 3, the linked list should become 1 -> 2 ->…

给定一个单链表,随机选择链表的一个节点,并返回相应的节点值.保证每个节点被选的概率一样.进阶:如果链表十分大且长度未知,如何解决这个问题?你能否使用常数级空间复杂度实现?示例:// 初始化一个单链表 [1,2,3].ListNode head = new ListNode(1);head.next = new ListNode(2);head.next.next = new ListNode(3);Solution solution = new Solution(head);// getRand…

1. 问题 给定一个单链表,随机返回一个结点,要求每个结点被选中的概率相等. 2. 思路 在一个给定长度的数组中等概率抽取一个数,可以简单用随机函数random.randint(0, n-1)得到索引来抽取. 本题是给定了链表,当然也好做,可以事先遍历一次求长度,每次要取的时候随机求索引,然后遍历一次. 时间复杂度O(n),空间复杂度O(1) 或者事先把数据放到数组中,每次要取的时候随机求索引,然后直接取到对应的数. 时间复杂度O(1),空间复杂度O(n) (延伸一下)如果对于长度未知,会不断增…

原题连接:https://www.patest.cn/contests/pat-a-practise/1074 题目: Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6, if K = 3, then you must output 3→2→1→6→…

Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6, if K = 3, then you must output 3→2→1→6→5→4; if K = 4, you must output 4→3→2→1→5→6. Input Specificat…

由于最近学的是线性结构,且因数组需开辟的空间太大.因此这里用的是纯链表实现的这个链表翻转. Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6, if K = 3, then you must output 3→2→1→6→5→4; if K = 4,…

Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6, if K = 3, then you must output 3→2→1→6→5→4; if K = 4, you must output 4→3→2→1→5→6. Input Specificat…

Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L.  For example, given L being 1→2→3→4→5→6, if K = 3, then you must output 3→2→1→6→5→4; if K = 4, you must output 4→3→2→1→5→6. Input Specifica…

上篇博文中讨论了链表的一些基本操作: 链表的基本操作(Basic Operations on a Linked List) 然而,为创建一个多功能的链表,在深度学习之前我们还需要了解更多的链表操作. 在表头插入元素. 在表中插入元素. 在确定的位置插入. 在某个元素的后面插入. 从链表中删除一个元素. 删除整个链表. 在链表头部插入元素 为了在链表头部插入元素,我们要完成一项小任务:创建一个临时节点,把数据存入这个临时节点,将这个节点指向链表的头节点. /* Defining a functio…

链表可以进行如下操作: 创建新链表 增加新元素 遍历链表 打印链表 下面定义了对应以上操作的基本函数. 创建新链表 新链表创建之后里面并没有任何元素,我们要为数据在内存中分配节点,再将节点插入链表.由于这个链表只有一个节点,它所指向的下一个节点为NULL. /* Defining a function to create a new list. The return type of the function is struct node, because we will return the h…

02-1. Reversing Linked List (25) 时间限制 400 ms 内存限制 65536 kB 代码长度限制 8000 B 判题程序 Standard 作者 CHEN, Yue Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6,…

1133. Splitting A Linked List (25) 时间限制 400 ms 内存限制 65536 kB 代码长度限制 16000 B 判题程序 Standard 作者 CHEN, Yue Given a singly linked list, you are supposed to rearrange its elements so that all the negative values appear before all of the non-negatives, and…

Design your implementation of the linked list. You can choose to use the singly linked list or the doubly linked list. A node in a singly linked list should have two attributes: val and next. valis the value of the current node, and next is a pointer…

Design your implementation of the linked list. You can choose to use the singly linked list or the doubly linked list. A node in a singly linked list should have two attributes: val and next. val is the value of the current node, and next is a pointe…

Convert a BST to a sorted circular doubly-linked list in-place. Think of the left and right pointers as synonymous to the previous and next pointers in a doubly-linked list. Let's take the following BST as an example, it may help you understand the p…

Given a singly linked list, you are supposed to rearrange its elements so that all the negative values appear before all of the non-negatives, and all the values in [0, K] appear before all those greater than K. The order of the elements inside each…

1. 原始题目 Design your implementation of the linked list. You can choose to use the singly linked list or the doubly linked list. A node in a singly linked list should have two attributes: val and next. val is the value of the current node, and next is …

［抄题］: Convert a BST to a sorted circular doubly-linked list in-place. Think of the left and right pointers as synonymous to the previous and next pointers in a doubly-linked list. Let's take the following BST as an example, it may help you understand…