Recently, I learnt about DP and started solving problems related to it. When I know the problem is on DP and then when I solve the question, I am surely able to find the recurrence relation, but when not specified, I am finding it difficult to identify whether the problem is on DP or not. How to distinguish whether a problem is on DP or greedy or ad hoc? And can somebody also provide links of good problems involving DP.

https://www.codechef.com/AUG16 Every month Codechef organises a Long Challenge of 10 questions. Many users of Codeforces do try the Long Challenges. As the discussion forums of Codechef is inactive than that of Codeforces, it would be nice if users discussed their solutions for the questions. Especially from task 5 as they usually have many different solution and it would be helpful for others too .