diff --git a/README.md b/README.md
index a7f1811..7d46933 100644
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@@ -1,5 +1,9 @@
 ## Data Structures and Algorithms for Online Programming Contest
-
+## bitmasking
++ left shift
++ right shift
++ divisible by 2 or not
++ general problems like subsequence problem
 ### Dynamic Programming
 + [Coin Change and variants](algorithms/coin_change.cpp)
 + [Knapsack Problem and variants](algorithms/knapsack.cpp)