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Title Description Given a string, please find out the length of the longest substring that does not contain duplicate characters. Type: "abcabcbb" Output: 3 Explanation: because the longest substring without repeating characters is "abc", its length is 3. Enter: "bbbbb" Output: 1 Explanation: b ...

Safety design of php interface The security of the interface is mainly designed around the three mechanisms of Token, Timestamp and ign, which ensure that the data of the interface will not be tampered with and called repeatedly. The following is specific: (1)Token authorization mechanism: (Token is the credential of the client to access the ...

package com.java.design.java8; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringRunner; import java.util.Arrays; import java.util.Compar ...

Unicode is a kind of character set coding. It is a character coding scheme developed by international organizations that can accommodate all the words and symbols in the world. It can represent any character. In java language, Unicode is composed of four hexadecimal digits, such as: u597d. java does not provide a tool class to d ...

Design sketch: 1. Define a class name expr, select dialog as the base class, or select the default class name and base class Click next to finish. The project is created. 2. Double click the. ui file in the interface file under the project file to enter the interface layout 3. Add buttons according to the functions you need to i ...

1. New features of ES6 (2015) class Modularization Arrow function Function parameter defaults Template string Destructuring assignment Extension operator Object attribute shorthand Promise Let and Const 1.1 module ES5 does not support native modularity, and modules are added as an important part of ES6. The function of the module is mainly co ...

Preface I believe that many back-end development projects will encounter the need to write api documents, whether it is to provide better docking for the front-end, mobile end, etc., or in the future for the convenience of handover, it will be required to write api documents. There are many pain points in handwritten api documents: When the do ...

python basic knowledge test In the process of using python, many basic knowledge does not need to be gradually unfamiliar. In order to enhance the familiarity, we do corresponding tests for each basic knowledge point of python, and constantly summarize and review.Knowledge points: Character string lis ...

leetcode Algorithmic Question 125 (Simple 033) Roman Number to Integer Topic introduction Given a string, verify that it is a palindrome string, only letters and numeric characters are considered, and the case of letters can be ignored. Note: In this topic, we define empty strings as valid palindrom ...

View system variables:1.env command [root@localhost ~]# env 2.set command [root@localhost ~]# set *set can display user-defined variables Custom variables: 1. Define variables: [root@localhost ~]# a=test [root@localhost ~]# echo $a test 2. Naming rules for variables: can include upper and lower case letters, numbers, underscores (cannot start ...