LashaBukhnikashvili's blog

By LashaBukhnikashvili, 10 years ago, In English

I'm trying to solve this porlbem,where you are interested the number of distinct elements in the subsequences.

I remember it was discussed,on codeforces but can't find it(not working "search by tag"),also I was looking in the Internet,but without result.please help me and discuss again or give me the links where already discussed. thank you in advance.