Hello, In this blog, I've tried to share my opinion on how to get good at dp problems, so stick to the end

in my opinion, dp is 85% thinking on paper, 10% thinking in your brain and 5% implementation.

so if you approach a dp problem always have pencil and paper and ** USE THEM** another thing is just solving the DP problems in combinatorics.

What do I mean?

**Question. 1** Given $$$n$$$, generate the set $$$s$$$ s.t $$$s = {1, 2, 3, 4, ..., n-1, n}$$$ then

count the number of subsets, where those elements in the set have *at least 1 element in between them*;

for example, $$$n = 8$$$ then $$$s = {1,2,3,4,5,6,7,8}$$$, one valid subset would be $$${1,4,8}$$$.

**Solution**

**Question. 2** Same as *Question 1* but should have *at least 2 elements in between them*

**Solution**

**Question. 3** Same as *Question 1*, Let's stop it

Let $$$a_n$$$ be the number of binary strings with *ab*, s. t no three consecutive characters are *a*.

find a recursive formula for $$$a_n$$$.

**Solution**

Since the problems I've are in Persian and translating them would be a pain, Message me and I'll send them to you if you want but the translation is on you

Hope this Helped

hi.Thank You