• ## Length of the last word of leetcode

Time：2022-7-24

order This article mainly records the length of the last word of leetcode subject Given a string s containing only uppercase and lowercase letters and spaces’ ‘, return the length of its last word. If the string scrolls from left to right, the last word is the last word. If there is no last word, […]

• ## Leetcode goat Latin

Time：2022-7-22

order This article mainly records the goat Latin of leetcode subject Given a sentence s with words separated by spaces. Each word contains only uppercase or lowercase letters. We want to convert the sentence into “goat Latin” (a fictional language similar to Pig Latin). The rules of goat Latin are as follows: If the word […]

• ## [number theory topic] bj-bn (basic computer test)

Time：2022-7-22

Bj: fractional matrix We define the following matrix:1/1 1/2 1/31/2 1/1 1/21/3 1/2 1/1The elements on the diagonal of the matrix are always 1/1, and the denominators of fractions on both sides of the diagonal increase one by one.Request the sum of this matrix.inputThe input contains multiple sets of test data. Each row is given […]

• ## Don’t miss the back end [pure dry goods] interview knowledge points sorting I

Time：2022-7-20

C++ interview questions Basic problems related to language Understanding of object reuse and zero copy object reuse It refers to design patterns. Objects can adopt different design patterns to achieve the purpose of reuse. The most common ones are inheritance and combination patterns. Zero copy: The main task of zero copy is to prevent the […]

• ## C language printf function and scanf function are simple to use

Time：2022-7-20

catalogue Introduction to printf function Scanf function Brief introduction to the principle of scanf function Introduction to printf function The printf function is output to the console Printf function is a standard library function of C language, which can output program operation results in an accurate format The calling format of printf function is: Printf […]

• ## This article will give you an intuitive understanding of linear transformation

Time：2022-7-19

The author is a master of software engineering. If there are mistakes in the article, please don’t hesitate to comment.This note is only for exchange and study. If you need to reprint it, please indicate the source. 1、 Definition of linear transformation Baidu Encyclopediaaboutlinear transformation The definition of is as follows: Linear mapping is from […]

• ## The relationship between constructor and instantiation and the introduction of prototype

Time：2022-7-18

My understanding of constructor and instantiation When our programming is object-oriented, First, the abstract process = > and then the instantiated process For example, if we abstract a person, I know the basic information of a person. Name, age, gender wait We first abstract it, and then instantiate it. The relationship between constructor and instantiation? […]

• ## Centos7 retrieve root password

Time：2022-7-16

In the boot interface, press“E” enter the editing interface   Press“E” enter the interface shown in the figure below, find the line beginning with “linux16”, and add “init=/bin/sh” after the line    After entering, press the shortcut keyCtrl+x enter single user mode Then enter the last lineMount -o remount, RW / note that there are […]

• ## Smartbi: get these data cleaning tips to quickly improve data quality!

Time：2022-7-14

Data cleaningHow to do (I): preparation After getting the data sheet, do these preparations first to facilitate the subsequent data cleaning. Name each sheet page for easy searching Add a row number to each worksheet to make it easier to change to the original order later Check the format of each column to ensure that […]

• ## [STL topic] – 02 relevant examples are selected from ACM

Time：2022-7-13

Produce champion There is a group of people, playing table tennis, catching and killing in pairs, and each two people can play at most one game.The rules of the game are as follows:If a defeats B, B defeats C, and there is no competition between a and C, then it is determined that a must […]

• ## [course notes] convex optimization of University of science and technology of China (II)

Time：2022-7-9

Affine set definition Equivalent definition:Solution set of linear equations$$C=\{x \mid A x=b\}$$Is an affine set, and the corresponding subspace is$$A$$Zeroing space of understand The line of any two points in the affine set is also in the affine set Affine combination of multiple points in affine set$$\theta_{1} x_{1}+\cdots+\theta_{k} x_{k},\theta_{1}+\cdots+\theta_{k}=1$$Also in the radiation set Proof idea: […]

• ## C# (V) Basics – string

Time：2022-7-9

C# This essay is for personal review and consolidation of knowledge. It is mostly summarized and understood from books. If there are mistakes, please correct them   C # string is a character array declared with string keyword. It is an object that encapsulates all string operations. C # string cannot be modified, and all […]