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原创 leetcode - 239. Sliding Window Maximum

239. Sliding Window MaximumGiven an array nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k numbers in the window.

2017-10-08 11:17:38 302

原创 C++ IO笔记

IO小结在C++中，IO操作主要有三个头文件，iostream fstream sstream iostream 包括istream ostream iostreamfstream 包括ifstream ofstream iofstreamsstream 包括istingstream ostringstreamg iostringstream 首先i带头的肯定就

2017-10-08 11:10:37 342

原创 opendaylight实现无线路由连接 -2

SDN无线网络连接这个实验文档说明了如何利用路由器WRT1900ACS连接无线节点。整体流程：1. 编译WRT1900ACS固件，并装好openvswitch2. 烧制路由器3. 安装好opendaylight4. ssh登录路由器修改配置文件5. 配置openvswtich6. 在opendayl

2017-06-29 16:52:25 825

原创 opendaylight实现无线路由连接 -1

这个实验文档说明了如何利用路由器WRT1900ACS连接无线节点。整体流程：1. 编译WRT1900ACS固件，并装好openvswitch2. 烧制路由器3. 安装好opendaylight4. ssh登录路由器修改配置文件5. 配置openvswtich6. 在opendaylight上查看无线节点

2017-06-29 16:36:07 563

原创 leetcode - 47. Permutations II(全排列)

47. Permutations IIGiven a collection of numbers that mightcontain duplicates, return all possible unique permutations. For example,[1,1,2] have the following uniquepermutations:[ [1,1,2],

2017-06-29 16:21:55 849

原创二级指针笔记

二级指针笔记这两天在leetcode上碰到一个这样的题目，Remove Nth Node From End of List，这个题目学习到了两种新的方法。1.路标标记法2.二级指针应用首先是关于路标标记，以后如果碰上这样一种情况，要从一个类似于链表结构的不可逆的对象的结尾开始取相对位置，则可以用一个先行路标p走X个位置，走了x位置之后再从新初始化一个对象q指向头部，那么

2017-05-22 15:52:08 295

原创 leetcode - 73. Set Matrix Zeroes

73. Set Matrix ZeroesGiven a m x n matrix,if an element is 0, set its entire row and column to 0. Do it in place.click to show follow up.Follow up:Did you useextra space?A straight forward s

2017-04-04 11:56:54 546

原创 leetcode - 64. Minimum Path Sum

64. Minimum Path SumGiven a m x n gridfilled with non-negative numbers, find a path from top left to bottom rightwhich minimizes the sum of all numbers along its path.Note: You can only move eithe

2017-03-25 09:57:30 293

原创 leetcode - 63.Unique Paths II

63.Unique Paths II Follow up for "Unique Paths": Now consider if some obstacles are added tothe grids. How many unique paths would there be? An obstacle and empty space is marked as 1and 0

2017-03-25 09:42:54 234

原创 leetcode - 62. Unique Paths

62. Unique Paths A robot is located at thetop-left corner of a m x n grid (marked 'Start' in the diagrambelow).The robot can only move either down or right at any point intime. The robot is tryi

2017-03-09 19:12:05 326

原创 leetcode - 57. Insert Interval

57. Insert IntervalGiven a set of non-overlapping intervals,insert a new interval into the intervals (merge if necessary). You may assume that the intervals wereinitially sorted according to the

2017-03-08 19:48:15 280

原创 leetcode - 56. Merge Intervals

56. Merge IntervalsGiven a collection ofintervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18]./** *Definition for an interval.

2017-03-07 19:12:12 227

原创 leetcode - 55. Jump Game

55. Jump GameGiven an arrayof non-negative integers, you are initially positioned at the first index ofthe array. Each element inthe array represents your maximum jump length at that position.

2017-03-03 13:13:13 315

原创 leetcode - 54. Spiral Matrix

54. Spiral MatrixGiven a matrix of m x n elements(m rows, n columns), return all elements of thematrix in spiral order.For example,Given the following matrix顺时针螺旋输出数组。比如[ [ 1,2, 3 ], [ 4

2017-03-02 21:08:40 277

原创 leetcode - 53. Maximum Subarray

53. Maximum SubarrayFind the contiguoussubarray within an array (containing at least one number) which has the largestsum.For example, given thearray [-2,1,-3,4,-1,2,1,-5,4],the contiguous subar

2017-03-01 17:38:01 324

原创 leetcode - 42. Trapping Rain Water

42. Trapping Rain WaterGiven n non-negative integers representing anelevation map where the width of each bar is 1, compute how much water it isable to trap after raining.For example, Given [0,1

2017-02-28 10:29:02 285

原创 leetcode - 41. First Missing Positive

41. First Missing Positive Given an unsorted integerarray, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should runin O(

2017-02-27 16:47:47 232

原创 leetcode - 40. Combination Sum II

40. Combination Sum IIGiven acollection of candidate numbers (C) and a target number (T),find all unique combinations in C where the candidatenumbers sums to T.Each number in C mayonly be used onc

2017-02-27 14:50:02 237

原创 leetcode - 39. Combination Sum

39. Combination SumGiven a set ofcandidate numbers (C) (without duplicates) and atarget number (T), find all unique combinations in C wherethe candidate numbers sums to T.The same repeatednumber

2017-02-27 11:10:34 365

原创 CCFCSP 201612-3权限查询

CCFCSP 201612-3权限查询问题描述　　授权 (authorization) 是各类业务系统不可缺少的组成部分，系统用户通过授权机制获得系统中各个模块的操作权限。　　本题中的授权机制是这样设计的：每位用户具有若干角色，每种角色具有若干权限。例如，用户 david 具有 manager 角色，manager 角色有 crm:2 权限，则用户 david 具有 crm:2 权限，

2017-02-06 14:53:16 1751

原创 leetcode - 35.Search Insert Position

35. Search Insert PositionGiven a sorted array and atarget value, return the index if the target is found. If not, return the indexwhere it would be if it were inserted in order.You may assume nod

2017-02-01 21:11:19 228

原创 leetcode - 34. Search for a Range

34. Search for a RangeGiven an array of integerssorted in ascending order, find the starting and ending position of a giventarget value.Your algorithm's runtime complexity must be in the order of

2017-01-31 11:52:39 234

原创 leetcode - 33. Search in Rotated Sorted Array

33. Search in Rotated Sorted ArraySuppose an array sorted inascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).You are given a

2017-01-31 10:59:04 190

原创 leetcode - 31 Next Permutation

31. Next PermutationImplement next permutation,which rearranges numbers into the lexicographically next greater permutation ofnumbers.If such arrangement is not possible, it must rearrange it as t

2017-01-31 10:31:33 262

原创 leetcode - 27 Remove Element

27. Remove ElementGivenan array and a value, remove all instances of that value in place and returnthe new length.Do not allocate extra space for another array, you must do thisin place with const

2017-01-31 09:36:01 287

原创 leetcode - 26 Remove Duplicates from Sorted Array

Remove Duplicates from Sorted ArrayGiven a sorted array,remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for another arr

2017-01-21 09:20:26 220

原创 leetcode -18 4Sum

4Sum Given an array S of n integers,are there elements a, b, c, and d in S such that a + b + c + d =target? Find all unique quadruplets in the array which gives the sum of target. 给定一个数组S里包含

2017-01-20 18:16:04 195

原创 leetcode -16 3Sum Closest

3Sum ClosestGiven an array S of n integers,find three integers in S suchthat the sum is closest to a given number, target. Return the sum of the threeintegers. You may assume that each input would h

2017-01-20 10:28:56 257

原创 leetcode -15 3sum

3SumGiven anarray S of n integers,are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in thearray which gives the sum of zero. 找到一个数组中3个数字。使得3个数字相加等于0。方法1：O（

2017-01-18 14:43:12 375

原创 leetcode 11 - Container With Most Water

Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that thetwo endpoints of line i isat (i, ai) and (i,0). Find two

2017-01-17 12:58:43 280

**机器中float的二进制舍入问题**在计算机中，对于精度取舍的问题一直都比较模糊，到底什么时候要舍去，什么时候要输出，下面我就以计算机中的float型为例子，来简单地说一说float的四舍五“入”。float型在计算机用32位来表示（4个字节），和计算机表示int长度相同，但是表示的机制完全不一样，它由sign，exp，frac部分组成，也就是我们所说的符号位，阶码位，和小数位。具体的表示方法

2016-04-19 22:24:21 2999

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