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graphReconstruct ItineraryCut Off Trees for Golf EventNumber of IslandsFriend CirclesWord LadderRedundant ConnectionEmployee ImportanceCourse ScheduleCourse Schedule IINetwork Delay Time

HeapTop K Frequent WordsFind Median from Data StreamGreedyCreate Maximum NumberCut Off Trees for Golf EventTask SchedulerLongest PalindromeValid Triangle NumberAssign CookiesMaximum Pr

reverse Linked Listbit operationreverse Linked List206. Reverse Linked List/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * L

669. Trim a Binary Search TreeGiven a binary search tree and the lowest and highest boundaries as L and R, trim the tree so that all its elements lies in [L, R] (R >= L). You might need to change the r

551. Student Attendance Record IProblem DescriptionYou are given a string representing an attendance record for a student. The record only contains the following three characters:'A' : Absent.'L' : La

646. Maximum Length of Pair ChainProblem DescriptionYou are given n pairs of numbers. In every pair, the first number is always smaller than the second number.Now, we define a pair (c, d) can follow an

Divide Two IntegersProblem DescriptionImplementation29. Divide Two IntegersProblem DescriptionDivide two integers without using multiplication, division and mod operator.If it is overflow, return MAX

Set MismatchProblem DescriptionImplementation645. Set MismatchProblem DescriptionThe set S originally contains numbers from 1 to n. But unfortunately, due to the data error, one of the numbers in the

292. Nim GameProblem DescriptionYou are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who rem

变量在作用域里面被声明的是什么类型，就当作什么类型来用。（1）参数是二维数组，但是要指定第二维的维数。int array[10][10];函数声明：void fuc(int a[][10]);函数调用：fuc(array);——在函数fuc中，a是二维数组。使用a[i][j]形式来访问数组中元素。（2）参数使用一维指针数组。int *array[10];for(i

用#include可以包含其他头文件中变量、函数的声明，为什么还要extern关键字,如果我想引用一个全局变量或函数a，我只要直接在源文件中包含#include首先说下头文件，其实头文件对计算机而言没什么作用，她只是在预编译时在#include的地方展开一下，没别的意义了，其实头文件主要是给别人看的。我做过一个实验，将头文件的后缀改成xxx.txt，然后在引用该头文件的地方用#include"x

617. Merge Two Binary TreesProblemGiven two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not.You need to me

Average of Levels in Binary TreeProblemImplementationSum of Square NumbersProblem DescriptionImplementationMaximum Average Subarray IDescriptionImplementation637. Average of Levels in Binary Tr

475. HeatersProblemWinter is coming! Your first job during the contest is to design a standard heater with fixed warm radius to warm all the houses.Now, you are given positions of houses and heaters on

606. Construct String from Binary TreeProblemYou need to construct a string consists of parenthesis and integers from a binary tree with the preorder traversing way.The null node needs to be represente

Task SchedulerProblemImplmentation621. Task SchedulerProblemGiven a char array representing tasks CPU need to do. It contains capital letters A to Z where different letters represent different tasks.

Maximum Product of Three NumbersProblemImplementation628. Maximum Product of Three NumbersProblemGiven an integer array, find three numbers whose product is maximum and output the maximum product.Exa

599. Minimum Index Sum of Two ListsdescriptionSuppose Andy and Doris want to choose a restaurant for dinner, and they both have a list of favorite restaurants represented by strings.You need to help th

Can Place FlowersdescriptionimplementationValid Triangle Numberdescriptionimplementation605. Can Place FlowersdescriptionSuppose you have a long flowerbed in which some of the plots are planted an

Reshape the Matrixdescriptionimplementation566. Reshape the MatrixdescriptionIn MATLAB, there is a very useful function called ‘reshape’, which can reshape a matrix into a new one with different size

Array Partition Idescriptionimplementation561. Array Partition IdescriptionGiven an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (a

Evaluate Reverse Polish NotationDescriptionImplementation150. Evaluate Reverse Polish NotationDescriptionEvaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators are

Binary Search Tree IteratorDescriptionImplementation173. Binary Search Tree IteratorDescriptionmplement an iterator over a binary search tree (BST). Your iterator will be initialized with the root no

Problem DescriptionImplementation By CProblem DescriptionImplement a basic calculator to evaluate a simple expression string.The expression string may contain open ( and closing parentheses ), the plu

DESCRIPTIONIMPLEMENTATION DESCRIPTIONGiven a binary tree, flatten it to a linked list in-place.For example,Given : 1 / \ 2 5 / \ \ 3 4 6The flattened tree sho

Reverse Words in a String IIIDESCRIPTIONIMPLEMENTATIONLongest Uncommon Subsequence IDESCRIPTIONIMPLEMENTATION557. Reverse Words in a String IIIDESCRIPTIONGiven a string, you need to reverse the or

Diameter of Binary Treedescriptionimplementation543. Diameter of Binary TreedescriptionGiven a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree i

Course Schedule IIDESCRIPTIONIMPLEMENTATION210. Course Schedule IIDESCRIPTIONThere are a total of n courses you have to take, labeled from 0 to n - 1.Some courses may have prerequisites, for example

Single Number IIDESCRIPTIONIMPLEMENTATIONUTF-8 ValidationDESCRIPTIONIMPLEMENTATION137. Single Number IIDESCRIPTIONGiven an array of integers, every element appears three times except for one, whic

Sum of Two IntegersDESCRIPTIONIMPLEMENTATIONMaximum Product of Word LengthsDESCRIPTIONIMPLEMENTATION371. Sum of Two IntegersDESCRIPTIONCalculate the sum of two integers a and b, but you are not al

站队终结者C站队有一条很长的队伍，队伍里面一共有n个人。所有的人分为三类：警察，小偷和普通人。将队伍里面的人从前到后由1到n编号，编号为i的人与编号为j的人的距离为i与j之差的绝对值。每一个警察有一个能力值x，表示他能够监视与他距离不超过x的所有人，小偷被警察发现当且仅当他被一个或多个警察监视到。你知道在整条队伍中，一共有多少个小偷会被警察发现吗？在【1】中有所有的2017年京东的题目。这道题目，

Continuous Subarray Sumdescriptionimplementation523. Continuous Subarray SumdescriptionGiven a list of non-negative numbers and a target integer k, write a function to check if the array has a contin

Number of BoomerangsDESCRIPTIONIMPLEMENTATION447. Number of BoomerangsDESCRIPTIONGiven n points in the plane that are all pairwise distinct, a “boomerang” is a tuple of points (i, j, k) such that the

Maximum XOR of Two Numbers in an Arraydescriptionimplementation421. Maximum XOR of Two Numbers in an ArraydescriptionGiven a non-empty array of numbers, a0, a1, a2, … , an-1, where 0 ≤ ai < 231.Find

descriptionimplementationdescriptionDesign a data structure that supports the following two operations:void addWord(word)bool search(word)search(word) can search a literal word or a regular expressi

Reverse BitsdescriptionimplementationVerify Preorder Serialization of a Binary Treedescriptionimplementation190. Reverse BitsdescriptionReverse bits of a given 32 bits unsigned integer.For example

题目描述代码实现题目描述Sort a linked list in O(n log n) time using constant space complexity.对一个链表进行排序，时间复杂度为O(n log n)，空间复杂度为O(1)，所以这道题目的限制还是比较多。由于链表的索引不是很方便，所以首先可以想到使用归并排序，那么时间复杂度为O(n log n)。然后又因为空间复杂度为O(1)，那么

Word Ladder II题目描述代码实现Perfect Number题目描述代码实现26. Word Ladder II题目描述Given two words (beginWord and endWord), and a dictionary’s word list, find all shortest transformation sequence(s) from beginWord

面向对象的思想面向对象的思想封装封装意味着把对象的属性和方法结合成一个独立的系统单位，并尽可能隐藏对象的内部细节。比如一个手电筒，我们不要关心它的内部实现机制，它的电路等等，我们只要了解开关（输入）和灯的亮度（输出）。抽象抽象的过程是对具体问题进行概括的过程，是对一类公共问题进行统一描述的过程。为了使某些必要的信息得以顺利的交流，设计者必须制定一个抽象，就如同一个协议，一个得到所有参与活动的有效个体

Find Minimum in Rotated Sorted Array II题目解析代码实现154. Find Minimum in Rotated Sorted Array II题目解析Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1