## Detailed explanation of differential constraint system

Differential constraint system
What is differential constraint system
Difference constraint system refers to a method to solve the following multivariate primary inequality system, in which (y1,y2... yn are constants), which is called difference because each inequality of multivariate primary inequality system is about the difference between ...

Added by **sevenupcan** on *Thu, 03 Mar 2022 17:01:29 +0200*

## Understand LSTM in one article

1, Write in front
This article introduces an improved version of RNN - LSTM on the basis of my other blog post "understanding RNN in one article"
2, LSTM
In the practical application of RNN, we find that when the number of time steps is large or the time steps are small, the gradient of cyclic neural network is prone to attenuation ...

Added by **sanstenarios** on *Thu, 03 Mar 2022 16:10:46 +0200*

## Chapter 1 basic algorithm

sort
Quick sort The core idea of fast platoon is divide and conquer. Choose one as a sentry, so that the number less than or equal to it is on the left and the number greater than or equal to it is on the right The time complexity is n(logn)
The steps are roughly divided into the following three steps:
Determine the dividing pointAdjust ...

Added by **sashi34u** on *Thu, 03 Mar 2022 15:42:46 +0200*

## Sorting algorithm notes - Advanced sorting

1. Hill sort
Hill sort is a kind of insertion sort, which is a more efficient sort algorithm
1.1 sorting principle
1. Select a growth amount h and group the data according to the growth amount h as the basis for data grouping 2. Insert and sort each group of data divided into groups 3. Reduce the growth to 1 at least, and repeat the operatio ...

Added by **ratass2002** on *Thu, 03 Mar 2022 15:21:58 +0200*

## Principal component analysis and its application in face recognition

Recently, I was studying Turing textbook by myself< Python Basic course of machine learning ", take some notes in the form of blog on csdn.
We may have many purposes in using unsupervised learning for data transformation. The most common purpose is to visualize, compress data, and find a more informative data representation for further ...

Added by **jateeq** on *Thu, 03 Mar 2022 13:47:38 +0200*

## [auxiliary exercise 3 of learning algorithms] Peking University POJ2956: repetition numbers

List of topics
1, Enumeration: 1753, 2965
2, Greedy: 2109, 2586
3, Minimum spanning tree: 2485, 1258
4, Sort: 2388
5, Deep optimization search: 1321, 2251
6, Breadth optimization search: 3278, 1426
7, Simple search techniques and pruning: 2676
8, Backpack problem: 1837
9, Topology sorting: 1094
10, Shortest path algorithm: 1 ...

Added by **Ironphp** on *Thu, 03 Mar 2022 09:57:28 +0200*

## Order number creation (php)

Simple order number creation (php):
function generateOrderSn()
{
$yearCode = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K"];
//Generate rule year (convert to an uppercase letter to shorten the length) + Month (convert to hexadecimal number) + day + after the current timestamp
//Several ...

Added by **sublimenal** on *Thu, 03 Mar 2022 09:21:37 +0200*

## CCF CSP certification 2020-09-2 "risk population screening" problem solving ideas and full score code

Problem description
Topic background
After the outbreak of an epidemic in a certain place, we want to inform all residents who have recently passed through the high-risk area to participate in nucleic acid testing in accordance with the principle of "testing as much as possible".
Problem description
In order to find out the re ...

Added by **Death_Octimus** on *Thu, 03 Mar 2022 08:22:13 +0200*

## 1. How to handle exceptions in Python? 2. What is exception handling in Python? 4. Some preliminary knowledge of when to use exception handling network programming

abnormal
1. What is an exception
An exception is a signal of a program error. Once an error occurs in the program, an exception will be generated. If it is not handled in the program, the exception will be thrown, and the operation of the program will be terminated. In Python, the exceptions triggered by errors are as follows There are t ...

Added by **gnunoob** on *Thu, 03 Mar 2022 07:31:11 +0200*

## Data structure one to many, tree (end)

Personal blog portal, welcome to visit
Tree:
Definition: a tree has at most one root node. The terminal of each path is called terminal node, also known as leaf node. A node that is neither a root nor a leaf is called an intermediate node, and the line between the node and the node is called an edge. From bottom to top, it is called height * ...

Added by **Ting** on *Wed, 02 Mar 2022 18:28:10 +0200*