docs: add Chinese translation

Author: yanglbme

README.md

@@ -17,9 +17,11 @@
 ## Introduction
 Complete solutions to [LeetCode](https://leetcode-cn.com/problemset/all/), [LCCI](https://leetcode-cn.com/problemset/lcci/) and [LCOF](https://leetcode-cn.com/problemset/lcof/) problems, updated daily.
 
+[中文文档](./README_CN.md)
+
 ## Solution Tree
-- [leetcode](https://github.com/doocs/leetcode/blob/master/solution/README.md)
-- [lcci](https://github.com/doocs/leetcode/blob/master/lcci/README.md) / [lcof](https://github.com/doocs/leetcode/blob/master/lcof/README.md)
+- [LeetCode](https://github.com/doocs/leetcode/blob/master/solution/README.md)
+- [LCCI](https://github.com/doocs/leetcode/blob/master/lcci/README.md) / [LCOF](https://github.com/doocs/leetcode/blob/master/lcof/README.md)
 
 ## Contributions
 I'm looking for long-term contributors/partners to this repo! Send me [PRs](https://github.com/doocs/leetcode/pulls) if you're interested! See the following:

README_CN.md

@@ -0,0 +1,49 @@
+<p align="center">
+  <a href="https://github.com/doocs/leetcode"><img src="./img/leetcode-doocs.png" alt="LeetCode-GitHub-Doocs"></a>
+</p>
+
+<p align="center">
+  <a href="https://github.com/doocs/leetcode"><img src="https://badgen.net/badge/langs/Java,C++,Python,JavaScript,Go,.../green?list=1" alt="languages"></a>
+  <a href="https://github.com/doocs/leetcode/stargazers"><img src="https://badgen.net/github/stars/doocs/leetcode" alt="stars"></a>
+  <a href="https://github.com/doocs/leetcode/issues"><img src="https://badgen.net/github/open-issues/doocs/leetcode" alt="issues"></a>
+  <a href="https://github.com/doocs/leetcode/network/members"><img src="https://img.shields.io/github/forks/doocs/leetcode.svg" alt="forks"></a>
+  <a href="https://github.com/doocs/leetcode/blob/master/LICENSE"><img src="https://badgen.net/github/license/doocs/leetcode?color=green" alt="LICENSE"></a><br>
+  <a href="http://makeapullrequest.com"><img src="https://badgen.net/badge/PRs/welcome/cyan" alt="PRs Welcome"></a>
+  <a href="https://doocs.github.io/#/?id=how-to-join"><img src="https://badgen.net/badge/organization/join%20us/cyan" alt="open-source-organization"></a>
+  <!-- <a href="#backers" alt="sponsors on Open Collective"><img src="https://opencollective.com/doocs-leetcode/backers/badge.svg" /></a> 
+  <a href="#sponsors" alt="Sponsors on Open Collective"><img src="https://opencollective.com/doocs-leetcode/sponsors/badge.svg" /></a> -->
+</p>
+
+## 项目介绍
+本项目包含 [LeetCode](https://leetcode-cn.com/problemset/all/)、[《程序员面试金典（第 6 版）》](https://leetcode-cn.com/problemset/lcci/)、[《剑指 Offer（第 2 版）》](https://leetcode-cn.com/problemset/lcof/)等题目的相关题解。所有题解均由多种编程语言实现，包括但不限于：Java、Python、C++、JavaScript、C#、Go，日常更新。
+
+[English version](./README.md)
+
+## 题解
+- [LeetCode](https://github.com/doocs/leetcode/blob/master/solution/README.md)
+- [LCCI](https://github.com/doocs/leetcode/blob/master/lcci/README.md) / [LCOF](https://github.com/doocs/leetcode/blob/master/lcof/README.md)
+
+## 参与项目
+如果你对该项目有兴趣，并且希望加入我们刷题大军，欢迎随时提交 [PR](https://github.com/doocs/leetcode/pulls)。请参考如下步骤：
+
+- 将本项目 <kbd>Fork</kbd> 到你的个人 GitHub 帐户，然后 <kbd>clone</kbd> 到你的本地机器；
+- 对项目做出一些变更，然后使用 git <kbd>add</kbd>、<kbd>commit</kbd>、<kbd>push</kbd> 等命令将你的变更提交到你的远程 GitHub 仓库；
+- 将你的变更以 PR 的形式提交过来，项目的维护人员会在第一时间对你的变更进行 review！
+- 你也可以参考 [CONTRIBUTING](https://github.com/doocs/.github/blob/master/CONTRIBUTING.md) 或者 [GitHub Help](https://help.github.com/en) 了解更多细节。
+
+<p align="center">
+  <a href="https://github.com/doocs/leetcode"><img src="./img/how-to-contribute.png" alt="how-to-contribute"></a>
+</p>
+
+[Gitpod.io](https://www.gitpod.io) 是一个免费的在线开发环境，你也可以使用它参与本项目。
+
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/doocs/leetcode)
+
+## 贡献者
+非常感谢以下所有朋友对本项目的贡献，你们是最可爱的人！
+
+<a href="https://opencollective.com/doocs-leetcode/contributors.svg?width=890&button=true"><img src="https://opencollective.com/doocs-leetcode/contributors.svg?width=890&button=false" /></a>
+
+## 许可证
+
+<a rel="license" href="https://github.com/doocs/leetcode/blob/master/LICENSE"><img alt="Creative Commons License" style="border-width:0" src="./img/cc-by-sa-88x31.png" /></a><br /><a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">知识共享 版权归属-相同方式共享 4.0 国际 公共许可证</a>。