Help Needed: ICL2015 Problem

Revision en1, by mochow, 2015-06-14 04:56:08

I was trying to solve this problem from ICL2015div2 finals. I understand this is a problem on combinatorics (and perhaps DP) but I could not find a way towards solution.

I am weak in DP problems. They seem overwhelming to me most of the times. An elaborate explanations will surely be helpful for me. :)