Programmer Think

background Yesterday, Xiao Feng received an interview call from a company. One of the interview questions was a little interesting. I'll share it with you here. The interview question is how to delete the specified element in ArrayList. At first glance, it sounds like a simple question, but if you don't actually step on the pit, you can easily ...

realization public class SelectionSort { public int[] selectionSort(int[] A, int n) { //Record minimum subscript value int min=0; for(int i=0; i<A.length-1;i++){ min = i; //Find the minimum value after the beginning of subscript i for(int j=i+1;j<A.length;j++){ ...

Title Description Give you the root node of the binary tree, root. Please design an algorithm to calculate the vertical traversal sequence of the binary tree. For each node located in (row, col), its left and right child nodes are located in (row + 1, col - 1) and (row + 1, col + 1). The root node of the tree is located at (0, 0). The ve ...

What is the difference between the declaration and definition of variables The definition of a variable allocates address and storage space for the variable, and the declaration of a variable does not allocate address. A variable can be declared in multiple places, But only in one place. join extern Modified is the declaration of a variable, ...

public float refund(E item) { return 0; } } FruitShop fruitShop = new FruitShop<>(); // This shop sells apples FruitShop stringShop = new FruitShop<>(); // This fruit shop sells mobile phones??? Of course not logical Because of our store generics E If there is no restriction, it will lead to mistakes. Let's put restr ...

**「reason:」** * Primary keys are usually added. Tables without primary keys have no soul * It is recommended to add the creation time and update time. Detailed audit and tracking records are useful. Ali's development manual also mentions this point, as shown in the figure ![](https://img-blog.csdnimg.cn/2020121620 ...

3,CSRF Because user identification is based on cookies, if cookies are intercepted, users will be vulnerable to cross site request forgery attacks. 5, Authentication mechanism based on token The token based authentication mechanism is similar to http protocol and is stateless. It does not need to retain the user's authentication informatio ...

Starting today, we will open up a new topic: professional skills of mobile architects in simple terms, with the goal of becoming an architect step by step, detailing the most direct use value of an architect's skills, horizontal peripheral knowledge and in-depth professional technology The most direct use value: I'm most afraid to see an arti ...

1. Abstract class rule of grammar Role of abstract classes 2. Interface rule of grammar Implement multiple interfaces Inheritance between interfaces Clonable interface and deep copy Shallow copy VS deep copy summary 1. Abstract class ======= rule of grammar There is no actual working method. We can design it as an abstract method ...

The client can also use the SAVE command to create a snapshot. The Redis server that receives the SAVE command will not respond to any other commands before the snapshot is created; Note: the SAVE command is not commonly used. Before the snapshot is created, Redis is blocked and cannot provide external services. 3. Configuration snapshot t ...