## Complete java version of Fourier transform function (FFT)

1. Preface This function is completely based on Java language and its related computing toolkit, and has been applied to practice. As we all know, when we need to analyze the signal, we basically use the Fourier change function, but based on the Java platform, there is a lack of relevant Fourier function, or although there are packages in some ...

Posted by **big_c147** on *Sun, 06 Mar 2022 10:43:43 +0100*

## leetcode weekly The 283rd game of Zhou Sai an Xian's quantization ~ simulation + mathematical calculation is really numb

๐ Content of this article: leetcode weekly Game 283 of Zhou Sai an Xian quantization ~ simulation + mathematical calculation ๐ Article column: leetcode weekly game punch in ๐ Last updated: February 27, 2022 leetcode weekly Game 282 of the week race grape City special session of the week race ~ simple simulation + application of hash tab ...

Posted by **michaellunsford** on *Sun, 06 Mar 2022 09:38:42 +0100*

## Algorithm - maximum common substring

Title Description
This topic is code completion. Please complete the source code given in the topic and copy it to the code box on the right. Select the corresponding compilation language (C/Java) and submit it. If the source code language given in the title is not unique, you only need to select one to complete and submit. After copying, dele ...

Posted by **Huuggee** on *Sun, 06 Mar 2022 08:17:07 +0100*

## The second week of 2022

A.Binary Tree
meaning of the title If the root is (a,b), the left child is (a+b,b) and the right child is (a,a+b). Given (m,n), the initial root is (1,1). From (1,1) to (m,n), you need to walk several times to the left subtree and several times to the right subtree. Problem solving ideas Idea 1: reverse thinking, from (m,n) to (1,1). Given (m, ...

Posted by **andymelton** on *Sun, 06 Mar 2022 07:04:04 +0100*

## 8 minutes to learn the longest common subsequence (with C + + source code, the one that runs directly)

Algorithm is really wonderful. It's easy to be addicted after learning. Of course, it's said on a simple premise. If I encounter that kind of problem, I also have a headache.
Today's plot is still the form of dialogue between teachers and students. In this way, I think it is more gradual and less abrupt. What do you think?
Now, students, let' ...

Posted by **dragon_sa** on *Sat, 05 Mar 2022 21:52:52 +0100*

## Summary of top ten sorting algorithms

Top ten sorting algorithms
Common sorting algorithms include bubble sort, selection sort, insertion sort, merge sort, quick sort, Hill sort, heap sort, count sort, bucket sort and cardinal sort
Bubble sorting
When adjacent elements are equal, they do not exchange positions, so bubble sorting is a stable sorting.
void bubbleSort(vector ...

Posted by **anujgarg** on *Sat, 05 Mar 2022 15:10:00 +0100*

## Section 9 of C + + - map / set (usage + underlying principle + simulation implementation)

With the foundation of the red and black trees in front, our task in this section is relatively easy.
Let's explain what Map and Set are with the help of network literature.
First of all, we need to know that the bottom layers of Map and Set are red and black trees.
It is a balanced binary search tree, that is, binary balanced search tree.
...

Posted by **astricks** on *Sat, 05 Mar 2022 14:30:08 +0100*

## Summary of double finger needling -- Taking LeetCode 27, 977, 15 and 18 as examples

The initial brush force deduction starts from the foundation, and the double pointer method is widely used in basic problems.
LeetCode 27, 977, 15 and 18 are the problems I have done in recent days, which can be well solved by double pointer method:
27:
It is equivalent to dividing the array into two parts: the first part is the valid p ...

Posted by **reinmedia** on *Sat, 05 Mar 2022 13:45:24 +0100*

## day10.2_java learning notes

1. Common methods of StringBuilder class
The StringBuilder append (any type) parameter is appended to a string, and becomes a string no matter what the parameter is written It is equivalent to the + operation in the string
public static void builderAppend(){
StringBuilder builder = new StringBuilder();
//The append method appends a st ...

Posted by **JasonMWaldo** on *Sat, 05 Mar 2022 13:36:39 +0100*

## Time complexity of algorithm

The time of the algorithm is complex
1. Time complexity
[] the concept of time complexity[~] time complexity rule (representation of big O)[~] common time complex calculations
(1) The concept of time complexity: The time complexity of the algorithm is a function, which describes the operation time of the algorithm. The time spent by an algor ...

Posted by **ggkfc** on *Sat, 05 Mar 2022 12:51:38 +0100*