Part of course:
Catering Contracts: Version 2π (IOI Training Camp 2008: India)
Problem in short:
Given a tree with N vertices, and 1 ≤ K ≤ N, we want to find the number of connected subgraphs of K vertices. N ≤ 2500 and K ≤ 90.
Check out the discussion responses for solution one hint at a time!