Update README.md

Author: zzzhangboya

README.md

@@ -34,7 +34,7 @@
 
 ### 基础算法篇 🐮
 
-- [二分搜索](./basic_algorithm/binary_search.md)
+- [二分搜索√](./basic_algorithm/binary_search.md)
 - [排序算法](./basic_algorithm/sort.md)
 - [动态规划√](./basic_algorithm/dp.md)
 - [图相关算法○](./basic_algorithm/graph/)