# QA Official

### VLAD Learning Summary and python Implementation

work needs, studied some very classic image retrieval algorithms, recorded one by one, to facilitate their review and communication. This blog post is about VLAD (Vector of Locally Aggregated Descriptors), that is, the vector of aggregated local descriptors. It is a process of using local descriptors of images such as SIFT, SURF, ORB, etc. to do some aggregation operations, and then using a long vector to represent an image.Representation of images into vectors is a prerequisite for image retrieval.

### java Abnormal Jump Steps (Thinking and Implementation)

https://qaofficial.com/post/2019/04/08/69531-java-abnormal-jump-steps-thinking-and-implementation.html 2019-04-08
topic descriptionOn this topic, the premise is that n steps will have an n-order jump method.The analysis is as follows: f (1) = 1f (2) = f (2-1)+f (2-2)//f (2-2) represents the number of times that the 2nd order jumps the 2nd order at a time. f(3) = f(3-1) + f(3-2) + f(3-3) ... f(n) = f(n-1) + f(n-2) + f(n-3) + ... + f(n-(n-1)) + f(n-n) Description: 1）

### plustoken to Centralize Wallet Move Brick Arbitrage Is a Fraud?Is it fake?Or is it a profiteering project?

https://qaofficial.com/post/2019/04/08/69565-plustoken-to-centralize-wallet-move-brick-arbitrage-is-a-fraudis-it-fakeor-is-it-a-profiteering-project.html 2019-04-08
I believe there will be some doubts about the search problem. This is the best time and the worst time. We missed bitcoin in 13 years, Ethereum in 14 years, Ripple in 15 years, ant coins and so on. We missed many opportunities to become rich. We didn't have the chance to become rich second generation, but we had the chance to make our children rich second generation. This question needs a serious answer.

### &amp;quot;Cheng Xuyuan&amp;#x27;s Life of Moving Bricks&amp;quot; VII. Miscellaneous Love Talks

https://qaofficial.com/post/2019/04/08/69577-ampquotcheng-xuyuanamp#x27s-life-of-moving-bricksampquot-vii.-miscellaneous-love-talks.html 2019-04-08
Some students reported that each article was written too short and read too fast.On these two issues, after I was in Thought for a long time, I also felt that it was necessary to say something.Yes-from Lu Xun's "Commemoration of the Prince of Liu Hezhen".As a man, so many people use short and fast to describe me, you can understand meThis kind of sad?When this reputation comes out, who will be willing to do with me and love to do things ~ ~ ~ right, I also wish I couldEnough to show you, prove that I am a real man, a L'homme du printemps.

### &amp;quot;Sword Finger Offer》JavaScript Actual Combat-Fibonacci number+Step Jump Problem

https://qaofficial.com/post/2019/04/08/69508-ampquotsword-finger-offerjavascript-actual-combat-fibonacci-number-step-jump-problem.html 2019-04-08
niuke net exercise portal topic descriptionSolutionMethod 1: Ordinary recursion, but Call stack overflow is easy to occur, and the speed will be slow as the number of call layers increases.The most obvious thing is that Niuke's recursive version on the Internet does not work. function Fibonacci(n) { /* 方法一 递归，但是容易出现调用栈溢出的情况*/

### Do I really understand java (1)

https://qaofficial.com/post/2019/04/08/69588-do-i-really-understand-java-1.html 2019-04-08
Is this really the Map I know? Open the door and ask a few questions first, so the purposeful research will be clearer.1. Have you used any other Map besides HashMap?2. How is the bottom layer of HashMap implemented?Is map disorder?4. How does Concurrent HashMap achieve thread safety? Have you used any other Map besides HashMap? interesting HashMap is very common in practice, even we often equate HashMap with Map.What

### Dynamic Programming (DP) Method for Step Jump

https://qaofficial.com/post/2019/04/08/69516-dynamic-programming-dp-method-for-step-jump.html 2019-04-08
Problem Description: A step has N steps. If you can jump 1 step at a time, you can also jump 2 steps. Find out how many jump methods there are in total  int ClimbStairs(int n) { int dp[3]={1,1}; if(n<2) { return 1; } for(int i=2;i<=n;i++) { dp[2]=dp[0]+dp[1]; dp[0]=dp[1]; dp[1]=dp[2]; } return dp[2]; }

### Image Retrieval Principle

https://qaofficial.com/post/2019/04/08/69625-image-retrieval-principle.html 2019-04-08
http://www.ruanyifeng.com/blog/2011/07/principle_of_similar_image_search.html https://www.zhihu.com/question/19726630

### Jump Step Problem+Abnormal Jump Step Problem Solution (Dynamic Programming Recursive+Non-Recursive)

https://qaofficial.com/post/2019/04/08/69497-jump-step-problem-abnormal-jump-step-problem-solution-dynamic-programming-recursive-non-recursive.html 2019-04-08
One, Step Jump Problem Topic Description: A step has a total of N levels. If you can jump 1 level at a time, you can also jump 2 levels.Find out how many total hops there are and analyze the time complexity of the algorithm. Through the description of the topic, it can be clearly seen that this is a Fibonacci sequence. Recursive Implementation: unsigned long long solution(int stageNum) { /

### Late 2016 Summary

https://qaofficial.com/post/2019/04/08/69587-late-2016-summary.html 2019-04-08
Summary is always painful and surprising. There was no habit of annual summary before. Now it is a good start to summarize once, even if it is a harvest. What did I do in 2016? 1. Complete a complete project (requirement, analysis, design, development, testing, on-line and operation) independently although this project still belongs to the company.But we have gained a lot. 2. Leave your comfortable and familiar environment and enter a strange environment.