original There are already many projects using Arduino to drive a 0.96-inch OLED screen to display various information. If we need to drive OLED to display images, logos, etc. whatever we want, here is a simple and general method. You need to use Image2Cp, a tool for converting images to CPP code. Component list Arduino×1 […]
Tag: bitmap
.NET high-performance development-bitmap index
First, let’s assume such a business scenario. Everyone should be familiar with air tickets. When purchasing air tickets, you first select your desired departure and arrival city and time, then select the cabin class (business class, economy class), and click Query. A flight list will appear. If you click on a flight at will, you […]
Implementing check-in through redis bitmap
Implementation ideas Our check-in function can be completely completed through mysql. CREATE TABLE `sign_record` ( `id` bigint NOT NULL AUTO_INCREMENT COMMENT ‘primary key’, `user_id` bigint NOT NULL COMMENT ‘userid’, `year` year NOT NULL COMMENT ‘Sign in year’, `month` tinyint NOT NULL COMMENT ‘Month of check-in’, `date` date NOT NULL COMMENT ‘check-in date’, `is_backup` bit(1) NOT […]
[[Hash Application] Bitmap/Bloom Filter]
Bitmap/Bloom filter bitmap bitmap concept Use of bitmaps Bitmap simulation implementation bloom filter Bloom filter concept Use of bloom filter Bloom filter simulation implementation Bitmap/Bloom Filter Application: Massive Data Processing Hash splitting Bitmap Bitmap concept Computers usually use bits as the smallest storage unit of data. There are only two binary states: 0 and 1. […]
[C++ and data structures] Bitmaps and Bloom filters
Table of Contents 1. Bitmap 1. The concept of bitmap 2. Implementation of bitmap ①.Basic structure ②、set ③、reset： ④、test ⑤. Question: ⑥. Advantages, disadvantages and applications of bitmaps: ⑦. Complete code and testing 2. Bloom filter 1. Proposal of Bloom filter 2. Implementation of Bloom filter ①.Basic structure ②. Implementation of three Hash functors ③、 […]
Customized udf and udaf function statistics uv in SPARK SQL (using bitmap)
Customized udf and udaf function statistics uv in SPARK SQL (using bitmap) When counting UVs in actual work, the count(distinct userId) method is generally used to count people, but this is not efficient. Suppose you are counting data in multiple dimensions. When one day you want to roll up the dimensions, then It is also […]
Redis Advanced (bitmap bloom filter)
Table of Contents 1. What is a Bloom filter? 2. Bloom filter characteristics 3. Usage scenarios of Bloom filter 4. Code practice, unity of knowledge and action 1. What is Bloom filter Bloom Filter is a probabilistic data structure with high space efficiency and fast processing speed, which is used to determine whether an element […]
Redis: Using BitMap to implement user check-in
BitMap We can complete the check-in function through mysql. For example, the following table A user’s check-in is a record. If there are 10 million users and the average number of check-ins per person per year is 10, then the amount of data in this table per year will be 100 million. Each check-in requires […]
Redis’s BitMap implements distributed Bloom filter
Bloom Filter is an efficient probabilistic data structure used to determine whether an element belongs to a set. It stores and queries data by using hash functions and bit arrays, has fast insertion and query speeds, and takes up relatively little space. Introduce dependencies <!–Section–> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-aop</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <!– Database […]
Chapter 6 Android–ImageView, Bitmap
ImageView, and the TextView and EditText introduced earlier, all inherit from View and are all subclasses of View. ImageView is a view used to render images. View can be understood as a view or control. 1. Simple to use Place an image under the drawable-xxhdpi folder: Set this picture to ImageView in xml, so that […]