diff --git a/CS notes/CS-index.md b/CS notes/CS-index.md
index d726816..d454ced 100644
--- a/CS notes/CS-index.md	
+++ b/CS notes/CS-index.md	
@@ -43,6 +43,7 @@ tag:#leetcode
 - [[$filename]]
 ```
  
+- [[Leetcode  Valid-Parentheses]]
 - [[Leetcode Best-Time-To-Buy-And-Sell-Stock]]
 - [[Leetcode First-Unique-Character-In-a-String]]
 - [[Leetcode Intersection-of-Two-Arrays-II]]
@@ -52,6 +53,7 @@ tag:#leetcode
 - [[Leetcode Merge-Two-Sorted-Lists]]
 - [[Leetcode Pascal's-Triangle]]
 - [[Leetcode Ransom-Note]]
+- [[Leetcode Remove-Duplicates-From-Sorted-List]]
 - [[Leetcode Remove-Linked-List-Elements]]
 - [[Leetcode Reshape-The-Matrix]]
 - [[Leetcode Reverse-Linked-List]]
@@ -82,6 +84,7 @@ tag:#DS tag:#coding_problem -tag:#template_remove_me
 - [[$filename]]
 ```
  
+- [[Leetcode  Valid-Parentheses]]
 - [[Leetcode Best-Time-To-Buy-And-Sell-Stock]]
 - [[Leetcode First-Unique-Character-In-a-String]]
 - [[Leetcode Intersection-of-Two-Arrays-II]]
@@ -91,6 +94,7 @@ tag:#DS tag:#coding_problem -tag:#template_remove_me
 - [[Leetcode Merge-Two-Sorted-Lists]]
 - [[Leetcode Pascal's-Triangle]]
 - [[Leetcode Ransom-Note]]
+- [[Leetcode Remove-Duplicates-From-Sorted-List]]
 - [[Leetcode Remove-Linked-List-Elements]]
 - [[Leetcode Reshape-The-Matrix]]
 - [[Leetcode Reverse-Linked-List]]