Is there any online judge where there is a clear classification of the problems according to various paradigms to be used to solve the problem for practising those paradigms? Or anything close to the requirement would also do . thanks .
yeah you can do practice at lightoj.com,that good for practice bcz problem are categories
You can use Codechef tags to find classification of problems based on author, area and difficulty. Codeforces also provides great classification of problems using tags. Also you can see Ahmed-aly which provides classification of problems from various sites like SPOJ,Codeforces, Topcoder and others.
It’s called USACO TRAINING PROGRAM