Input: A universal set S={e1, e2,…,en } and set C={c1,c2,…,cm} where ci ⊂ S. Output: Number of sets in C’ ⊂ C such that ∪ ci=S where C’ is the minimum cardinality set. ci ∈C’
eg:Input: S = {1,2,3,4,5,6} C = {{1,2},{2,3},{4,5},{1,2,3,,4,5},{1,4,6},{3,4,5,6}} Output: 2