Update README.md

Author: hyebin-dev

README.md

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 # java-practice
+![Java CI](https://github.com/hyebin-dev/java-practice/actions/workflows/java-ci.yml/badge.svg)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)
+
 ## 바로가기
 - Week01: [basic](./week01/basic) · [intermediate](./week01/intermediate) · [advanced](./week01/advanced)
+
+## 소개
+주차별 Java 문제풀이(자료구조·알고리즘 중심) 저장소입니다.  
+
+## 폴더 구조
+```
+week01/
+  basic/         # 기초 문제
+  intermediate/  # 중급 문제
+  advanced/      # 심화 문제
+week02/
+  basic/
+  intermediate/
+  advanced/
+```
+
+## 커밋 규칙
+- **문제 1개 = 커밋 1개** 권장  
+- 예) `feat(week02/basic): add ReverseString.java`
+
+## 링크
+- 블로그: https://hyebin-dev.github.io
+- Projects: https://hyebin-dev.github.io/projects