diff --git a/README.md b/README.md
index c7c95cec..e4247dcc 100644
--- a/README.md
+++ b/README.md
@@ -797,9 +797,12 @@ Some data mining competition platforms
 - [DrivenData](https://www.drivendata.org/)
 - [Data Science Society](https://www.datasciencesociety.net/)
 - [Reddit-Data Science](https://www.reddit.com/r/datascience/)
+- [Stack Overflow](https://stackoverflow.com/)
+- [CSDN](https://www.csdn.net/)
 
 ## Algorithm Communities
 - [Commonlounge Algorithm Community](https://www.commonlounge.com/community/919705a0927646f9b49853ba13793b36)
 - [Hackr.io Algorithm Tutorials](https://hackr.io/tutorials/learn-data-structures-algorithms)
 - [Youth4Work Alogrithm Forum](https://www.youth4work.com/Talent/Data-Structure/Forum)
+- [Leetcode](https://leetcode.com)