Source code analysis of leveldb Arena

Preface Memory usage is very important for a high performance server program. C++ provides new/delete to manage memory application and release, but for small objects, the direct use of new/delete costs a lot, requires extra space and time, and the cost-effective ratio is not high. In addition, memory fragmentation caused by multiple applicatio ...

Posted on Sat, 03 Aug 2019 02:42:11 -0700 by arnihr

LeetCode 2 - Addition of Two Numbers (JAVA)

Two non-empty linked lists are given to represent two non-negative integers. Among them, their respective digits are stored in reverse order, and each of their nodes can only store one digit. If we add the two numbers together, we return a new list to represent their sum. You can assume that neither of these numbers will begin with zero excep ...

Posted on Sat, 03 Aug 2019 01:19:38 -0700 by ephmynus

CodeForces 527C. Glass Carving (SBT, Segment Tree, set, Maximum Continuous 0)

Origin address: http://codeforces.com/problemset/problem/527/C   Examples input 4 3 4 H 2 V 2 V 3 V 1 output 8 4 4 2 input 7 6 5 H 4 V 3 V 5 H 2 V 1 output 28 16 12 6 4   Given a rectangle, cut longitudinally or horizontally, ask what is the maximum rectangular area after each cut. Maximum rectang ...

Posted on Fri, 02 Aug 2019 01:42:16 -0700 by Stressed

Netty memory pool and allocation of hit cache

Memory specifications for memory pools: In the previous source code analysis process, we should have some impressions about the size of memory specifications. In fact, there are four main sizes of memory in Netty memory pool: tiny refers to the size between 0-512Byte, small refers to the size between 512Byte-8KB, normal refers to the size betw ...

Posted on Thu, 01 Aug 2019 21:48:03 -0700 by RogerInHawaii

Pre Background System Learning Notes

Docker Packaging Deployment Steps1. mvn clean package2. Transfer the jar package under the pre-alpine folder under target and the Dockerfile to a path on the server3. cd to path4.Build mirror docker build-t pre:1.0.5. Run the command docker run --name pre-P 8081:8081-d pre:1.0 Real product-level dockerfile #Basic MirrorFROM java:openjdk-8-jre ...

Posted on Thu, 01 Aug 2019 16:41:11 -0700 by apenster

Graph Theory Learning Notes

Recently, Ben Ming reviewed Graph Theory and found that he had forgotten it, so he planned to write such a learning note to review it. 1. Representation of Graphs 1. Adjacency Matrix Edges are stored in a two-dimensional array with \(map[i][j]=k\) representing the point\(i\) to point\(j\) weighting \(k\).Edge-adding and edge-checking complexity ...

Posted on Thu, 01 Aug 2019 11:50:33 -0700 by DanArosa

MapReduce programming model & WordCount example

Learn MapReduce, the first programming thought that big data comes into contact with.   Preface Previously, when learning big data, a lot of things made some scattered notes, but they were not well organized. This article is also a sort of previous notes, or called output.One is to deepen your understanding, the other is to hope that these ...

Posted on Wed, 31 Jul 2019 16:41:38 -0700 by erikjan

ansible's playbook uses, judges, loops, and roles

ansible 3rd playbook Conditional Judgment, Cycle and roles Hierarchical Management 1. ansible playbook's judgment, cyclic syntax: In ansible playbook, when syntax can be used to make judgments and loops through with_items, with the following examples: --- vim httpd_v4.yaml - hosts: websrvs remote_user: '{{uservar}}' vars: ...

Posted on Wed, 31 Jul 2019 16:12:16 -0700 by abolmeer

Data Structure and Algorithmic Analysis - C Language Description ADT Implementation (NO.02): Queue

Third structure - Queue The queue, in contrast to the last stack, is a linear first-in-first-out (FIFO).Only the tail is exposed when writing and only the head when reading.   Only queues in the form of arrays are implemented this time.The reason is that queues in the form of chained lists are so simple that you only need to delete the first ...

Posted on Wed, 31 Jul 2019 10:21:05 -0700 by Al42

Shortest Distance from All Buildings

You want to build a house on an empty land which reaches all buildings in the shortest amount of distance. You can only move up, down, left and right. You are given a 2D grid of values 0, 1 or 2, where: Each 0 marks an empty land which you can pass by freely. Each 1 marks a building which you cannot pass through. Each 2 marks an obstacle wh ...

Posted on Wed, 31 Jul 2019 10:15:05 -0700 by pkSML