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Introduction This article is a study note written after learning the article of the big guy and doing it yourself. The article of the big guy is well written. I can't describe it clearly by myself, so many parts of this article directly quote the article of the big guy. Source code: https://github.com/LinYaoTian... Design sketch: Tip: it's best ...

find() Model.find(filter[, projection][, options][, callback]) Parameter 1: filter The query condition uses the format of JSON document, and the syntax of JSON document follows MongoDB shell The same is true. { field1: value1, field2: { operator: value2 } ... } 1. Find all Model.find() Model.find({}) 2. Accurate search Model.find({author:'dora' ...

Now there are three main login methods: account password login, SMS verification code login and third-party authorized login. The previous section Spring security (3) -- authentication process We have analyzed the spring security account password mode login. Now let's analyze the spring security SMS mode authentication login.   &emsp ...

Ordered list: Sort by key. When the chain head is deleted, the minimum (/ maximum) value is deleted. When inserting, the insertion position is searched. When inserting, you need to compare O(N), average O(N/2), and delete the minimum (/ maximum) data in the chain head with an efficiency of O(1), If an application needs frequent access to (ins ...

SummaryMany readers ask me for the Demo source code of the Gin framework Practice Series in the background. Let me explain again here. I updated the source code to GitHub at https://github.com/xinliangnote/GoStarting today's article, why do you want to customize error handling? What is the default error handling method?Well, let's talk about de ...

What is a tree? Tree data structure is very common in life, such as going to the library to find a book, which is placed according to different categories. For example, the disk folder in the computer and so on. Using a tree structure to store data can be surprisingly efficient. As the name implies, the data structure of tree is like an inverte ...

Title Link Solving problems There are many ways to solve this problem. First of all, let's think about it. If it's more than 15, it will output - 1. Then let's find the minimum value. Obviously. It can be done with iteration deepening. We can enumerate the minimum steps directly. But that's only 20 points... You know, if t ...

First appeared in the WeChat public's front-end growth notes, written in 2019.11.13 background This paper records the whole thinking process in the process of writing questions for reference. The main contents include: Assumption of topic analysis Write code validation Consult others' solution Thinking and summing up Catalog 35. Search inser ...

Logu Title Link loj End Title Link Topic: Play a chess game on one axis.Chess pieces can only be placed on the whole point.No more than one piece can be placed at each point.Complete with Chess: There are 3 pieces on the board, in the three positions a, b and c.We want to move their positions to x, y, z with the least jumps. Rule of Jump: Selec ...

Original title: http://codeforces.com/gym/101848/problem/E Title: There are 2n dishes with their own prices. Each day, N dishes will be randomly selected. You have p yuan now. You can charge money first and then have a meal or not every day. Ask if you can make the balance zero in 365 days. Analysis: First of all, it is the requ ...