A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 思路：第一遍正常复制链表，同一时候用哈希表保存链表中原始节点和新节点的相应关系

题目 Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that ha

Majority Element II Given an integer array of sizen, find all elements that appear more than⌊ n/3 ⌋times. The algorithm should run in linear time and in O(1) space. leetcode 518，Hint: How many majority elements could it possibly have?跟出现超过一半的数

注：记录的都是写不出来的或者超时的 1---507.完美数 leetcode c++，对于一个正整数，如果它和除了它自身以外的所有正因子之和相等，我们称它为“完美数”。 给定一个正整数n，如果他是完美数，返回True，否则返回False 示例： 输

2019独角兽企业重金招聘Python工程师标准>>> Given an array of integers, every element appearsthreetimes except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you implement it without using extra

2019独角兽企业重金招聘Python工程师标准>>> Given an array of integers, returnindicesof the two numbers such that they add up to a specific target. You may assume that each input would haveexactlyone solution. Example: Givennums=[2,7,11,15],ta

Description Given two arrays, write a function to compute their intersection. Example:Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2]. leetcode 13。Note:Each element in the result must be unique.The result can be in any order. My solution

题目如下： There are 8 prison cells in a row, and each cell is either occupied or vacant. Each day, whether the cell is occupied or vacant changes according to the following rules: If a cell has two adjacent neighbors that are both occupied or both

算法描述： Evaluate the value of an arithmetic expression inReverse Polish Notation. Valid operators are+,-,*,/. Each operand may be an integer or another expression. Note: Division between two integers should truncate toward zero.The given RPN

The Question is: Given a string, find the length of the longest substring without repeating characters. Examples: Given “abcabcbb”, the answer is “abc”, which the length is 3. Given “bbbbb”, the answer is “b”, with the length of 1. LEETCODE？Given