Alexandar May's Blog

CS229 Notes (Part 1): Mathematical Basics of Linear Regression — From Model Formulation to Gradient Descent

Posted on 2025-10-19 In Machine Learning , Stanford CS229 Notes
Symbols count in article: 11k Reading time ≈ 10 mins.

• 1. Introduction:
  • 1.1 Welcome to the world of Machine Learning
  • 1.2 What Is Machine Learning?
  • 1.3 Supervised Learning
  • 1.4 Unsupervised Learning
• 2. Linear Regression with One Variable
  • 2.1 Model Representation
  • 2.2 Cost Function
    • 2.2.1 Definition of the Cost Function
  • 2.3 Intuition for the Cost Function (I)
  • 2.4 Intuition for the Cost Function (II): Contour Plots
  • 2.5 Gradient Descent
  • 2.6 Gradient Descent Intuition
  • 2.7 Gradient Descent for Linear Regression

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Hexo Blog Multi-Device Synchronization and Management Guide Based on Git Branch Strategy

Posted on 2025-05-03 In Blog , Hexo
Symbols count in article: 11k Reading time ≈ 10 mins.

• Introduction: The Necessity of Multi-Device Collaboration
• Core Principles of Hexo Multi-Device Synchronization
  • Hexo Directory Structure and Version Control Strategy
  • Git Branch Division of Labor Model
• Old Computer Operation Guide: Building Remote Synchronization Foundation
  • Creating and Configuring Remote Branches
  • Local Environment and Remote Repository Synchronization
  • .gitignore Key Configuration
• New Computer Environment Setup: Restoring Blog from Remote Repository
  • SSH Key Configuration and Environment Dependency Installation
  • Remote Repository Cloning and Dependency Recovery
  • First Run Verification and Configuration Check
• Daily Update Workflow: Dual Branch Collaborative Operation
  • Source Code Update and Submission Process
  • Static File Deployment and Branch Synchronization
  • Automation Script to Optimize Workflow
• Common Problems and Solutions
  • Branch Switching Conflict Handling
  • Environment Dependency Inconsistency Issue
  • Theme and Plugin Synchronization Abnormality
• Advanced Tips: Private Repositories and Multi-Branch Strategies
  • Private Repositories to Protect Source Code Security
  • Multi-Branch Collaborative Development Model
• Conclusion: Best Practices for Multi-Device Synchronization
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Common Binary Tree Problems

Posted on 2025-04-26 In Data Structure and Alogrithm , Binary Tree
Symbols count in article: 12k Reading time ≈ 11 mins.

1. Introduction
2. Case Study
   • Invert Binary Tree
   • Symmetric Tree
   • Maximum Depth of Binary Tree
   • Minimum Depth of Binary Tree
   • Count Complete Tree Nodes
   • Balanced Binary Tree
   • Binary Tree Paths
   • Sum of Left Leaves
   • Find Bottom Left Tree Value

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Design Patterns

Posted on 2025-04-19 In Design Patterns , Software Design
Symbols count in article: 49k Reading time ≈ 45 mins.

1. Introduction
   • Types of Design Patterns
   • Key Characteristics of Design Patterns
2. Creational Patterns
   • Factory Pattern
   • Abstract Factory Pattern
   • Builder Pattern
   • Singleton Pattern
3. Structural Patterns
   • Adapter Pattern
   • Bridge Pattern
   • Composite Pattern
   • Decorator Pattern
   • Facade Pattern
   • Flyweight Pattern
   • Proxy Pattern
4. Behavioral Patterns
   • Observer Pattern
   • Iterator Pattern
   • Command Pattern
   • Strategy Pattern
   • State Pattern
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Stack & Queue

Posted on 2025-04-12 In Data Structure and Alogrithm
Symbols count in article: 7.6k Reading time ≈ 7 mins.

1. Introduction
2. Stack Overview
   • Key Features
   • Applications
3. Queue Overview
   • Key Features
   • Applications
   • Types of Queues
4. Implementing Stack
   • With Array
   • With Linked List
5. Implementing Queue
   • With Array
   • With Linked List
6. Implementing Queue with Two Stacks
7. Implement Stack using just one Queue
8. Summary
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Hash Table

Posted on 2025-04-05 In Data Structure and Alogrithm
Symbols count in article: 11k Reading time ≈ 10 mins.

1. What is Hash Table
   • Core Concepts
   • Common operations of hash table
2. Hash Collision
   • Separate Chaining
   • Open Addressing
3. Hash Alogrithm
   • Goals of hash algorithms
   • Common hash algorithms
4. Practical Examples
   • four sum
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