LeetCode Animation — User Guide

1. Quick Start

LeetCode Animation is a curated collection of approximately 100 LeetCode algorithm problems, each explained through animated GIF/video visualizations and detailed markdown articles (in Chinese). Many problems include reference Java implementations. The repository is maintained by MisterBooo (吴师兄) and serves as a visual algorithm learning resource.

Key features:

• Animated GIF/MP4 visualizations showing algorithms step-by-step
• Detailed markdown articles explaining solution logic and complexity
• Reference Java implementations for selected problems
• Consistent per-problem folder structure: Animation/, Article/, Code/
• Coverage across arrays, linked lists, trees, dynamic programming, stacks, graphs, and bit manipulation
• Python CLI scaffolding tool for contributors to create new solution entries

Prerequisites: Git (to clone), any markdown viewer or browser (to read)

Fastest path — browse online:

Open the repository on GitHub and navigate any problem folder. The Animation/ directory contains the teaching GIF; the Article/ directory contains the written walkthrough.

Clone for offline use:

git clone https://github.com/MisterBooo/LeetCodeAnimation.git
cd LeetCodeAnimation

Open any problem folder (e.g., 0001-Two-Sum/Animation/Animation.gif) to see the algorithm animated.

Tip

You do not need Python, Java, or any dependencies to read existing solutions. Just clone and browse — the entire collection is static markdown and media files.

2. Installation

Reading Solutions (No Install Required)

Important

The repository is approximately a few hundred MB due to GIF and video animation files. Use a sparse checkout if you only need specific problems (see Common Tasks).

Scaffolding Tool (Contributors Only)

To use the anima.py CLI for creating new problem scaffolds:

cd LeetCodeAnimation
pip install -r requirements.txt

The requirements.txt contains a single dependency: fire (Google's Python Fire CLI library).

Verify installation:

python anima.py --help

NAME
    anima.py

SYNOPSIS
    anima.py COMMAND

COMMANDS
    COMMAND is one of the following:
     new

3. Core Usage

Problem Folder Structure

Each LeetCode problem lives in a directory named {number}-{Problem-Name}/ with up to three subdirectories:

Example — Two Sum (Problem 1):

0001-Two-Sum/
├── Animation/
│   └── Animation.gif
└── Article/
    └── 0001-Two-Sum.md

Note

Articles are written in Simplified Chinese. The animations and code samples are language-agnostic. Use a browser translation extension for the articles if needed.

Browsing by Category

Tip

Problem directories use zero-padded LeetCode numbers (e.g., 0042-Trap/). Use ls | grep 0042 or your file manager's search to find a specific problem quickly.

Reading a Problem

The recommended learning flow for each problem:

1. Watch the animation — open Animation/Animation.gif for a visual walkthrough of the algorithm (5–20 seconds, looping)
2. Read the article — open the markdown file in Article/ for the detailed explanation with complexity analysis
3. Study the code — if a Code/ subfolder exists, review the reference Java implementation

The notes/ Directory

The notes/ directory contains 68 standalone Chinese-language write-ups covering additional problems beyond those with full animation treatment. These follow a different format — article-only, no animations. File names use the pattern LeetCode第{id}号问题：{title}.md.

Warning

The most recent commit to this repository is fd42771 (2022-01-12). The content remains accurate as an algorithm learning resource, but no new problems are being added.

Creating New Solution Scaffolds (Contributors)

The anima.py CLI creates a correctly structured directory for a new problem:

python anima.py new <problem_id> "<problem_title>"

Example:

python anima.py new 121 "Best Time to Buy and Sell Stock"

题解框架创建完毕，位于文件夹 /path/to/LeetCodeAnimation/0121-Best-Time-to-Buy-and-Sell-Stock

This creates:

0121-Best-Time-to-Buy-and-Sell-Stock/
├── Animation/
│   ├── Animation.gif    (empty placeholder)
│   └── Animation.m4v    (empty placeholder)
├── Article/
│   └── 0121-Best-Time-to-Buy-and-Sell-Stock.md    (copied from template)
└── Code/

4. Common Tasks

Find a Specific Problem by Number

ls | grep "^0146"

0146-LRU-Cache

Download a Single Problem Without Cloning Everything

git clone --depth 1 --filter=blob:none --sparse \
  https://github.com/MisterBooo/LeetCodeAnimation.git
cd LeetCodeAnimation
git sparse-checkout set 0001-Two-Sum

View an Animation Frame-by-Frame

Open the .gif file in any image viewer that supports animated GIF playback. Some problems also include .m4v or .mp4 video files in Animation/ for higher-quality playback at adjustable speed.

Search Articles by Topic

# Find all linked-list articles in notes/
grep -l "链表" notes/*.md

notes/LeetCode第019号问题：删除链表的倒数第N个节点.md
notes/LeetCode第021号问题：合并两个有序链表.md
...

Contributing a New Solution

1. Fork the repository on GitHub
2. Scaffold a new problem: python anima.py new <id> "<title>"
3. Create your animation (GIF format preferred) and place it in Animation/
4. Write the article in the generated markdown file under Article/
5. Optionally add a code solution under Code/
6. Submit a pull request

Note

Pull requests are not actively being reviewed since the repository has been inactive since January 2022.

5. Troubleshooting

Error: 创建失败，文件夹 ... 已存在

Cause: The anima.py CLI refuses to create a folder when one already exists for that problem ID and title.

Solution:

1. Check if the problem already has a solution: ls | grep "^{number}"
2. If you need to recreate it, manually delete the existing directory first

Prevention: Always check for existing solutions before scaffolding.

Error: ModuleNotFoundError: No module named 'fire'

Cause: The fire dependency is not installed.

Solution:

pip install -r requirements.txt

Warning

If you use multiple Python environments, ensure you install into the correct one. Use python -m pip install fire to target the right interpreter.

Problem: Animation GIFs in the README do not load

Cause: README-embedded animations may be hosted on external CDN infrastructure. From some networks — particularly outside mainland China — these URLs can be slow or unreachable.

Solution: Clone the repository and view animations directly from {problem-folder}/Animation/Animation.gif. The local files are the authoritative copies.

Problem: Broken images in Problem 23

Cause: Community issue #104 reports broken images for Problem 23 (Merge k Sorted Lists).

Solution: The 0023-Merge-k-Sorted-Lists/ folder in the repository contains the local animation file — view it directly rather than via the README embed.

Caution

Since the repository is no longer actively maintained, open issues like #104 are unlikely to be resolved by the author. Local copies of animations are always the reliable fallback.

Problem: Cannot read Chinese articles

Cause: Articles are written in Simplified Chinese with no official English translation.

Solution: Use a browser translation extension (Chrome Translate, Edge Immersive Translator) on GitHub's rendered markdown view. Code blocks pass through untranslated.

6. FAQ

Q: Do I need to know Chinese to use this repository?

The animations (GIFs) and code solutions are language-agnostic and useful regardless of language fluency. Only the article write-ups require Chinese reading ability (or a translation tool). An English README (README-En.md) provides an index of problem titles.

Q: What programming languages are the code solutions in?

Almost all code solutions in Code/ directories are Java (.java). One C++ solution exists for Problem 215 (Kth Largest Element in an Array).

Q: Are all LeetCode problems covered?

No. The repository covers approximately 100 selected problems, focusing on commonly asked interview classics. The notes/ directory contains an additional ~68 article-only write-ups. Problems above roughly #1400 are out of scope.

Q: Is this project still actively maintained?

The last commit is from January 2022. The content remains accurate as a learning resource since algorithm solutions do not change, but no new problems are being added.

Q: What is the template/template.md file?

It is the markdown template that anima.py copies into each new problem's Article/ directory when scaffolding. It provides the starting structure: problem statement, analysis, animation walkthrough, reference code, and complexity analysis.

Q: Do the animations have audio?

No. Animations are silent GIFs (or MP4/M4V where present). The written article serves as the narration.

Q: What does the anima folder do?

It is a small Python package (~100 lines) that contributors use to scaffold new problem folders with the correct directory structure. Readers do not need to interact with it. See the Admin Guide for technical details.

Q: Is there a recommended reading order?

No prescribed order exists. A practical approach: start with Easy problems in ID order (Two Sum, Valid Parentheses, Merge Two Sorted Lists), then tackle Medium classics (LRU Cache, Longest Substring Without Repeating Characters, 3Sum).