added Dynamic Programming Book (bengali) (#5244)

books/free-programming-books-bl.md

 ### Index
 
 * [C](#c)
+* [Competitive Programming](#competitive-programming)
 * [JavaScript](#JavaScript)
 * [Machine Learning](#machine-learning)
 * [Misc](#misc)
@@ -12,6 +13,11 @@
 * [Computer Programming](http://cpbook.subeen.com/p/blog-page.html) - Tamim Shahriar Subeen 
 
 
+### Competitive Programming
+
+* [Dynamic Programming Book](https://dp-bn.github.io) - Tasmeem Reza and Mamnoon Siam 
+
+
 ### JavaScript
 
 * [হাতেকলমে জাভাস্ক্রিপ্ট](https://zonayed.js.org) - Zonayed Ahmed