> For the complete documentation index, see [llms.txt](https://zichao-yang.gitbook.io/leetcode-zichao/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zichao-yang.gitbook.io/leetcode-zichao/readme.md).

# Introduction

* [Read this in Gitbook](https://zichao-yang.gitbook.io/leetcode-zichao/)
* [Zichao Yang's Homepage](https://www.zichaoyang.com/)

## Meaning of Table of Contents

* 'J' means I've done it in Java.
* 'P' means I've done it in Python3.
* '?' means there are some other good method worth trying.

  For example, 001J? means I only finished p001 with some trivial method in Java, while 001JP means I've thoroughly done this problem in both Java and Python3.
* 'x' means this problem is not worth wasting time on it.
* '\* ' means this problem has been considered thoroughly.