The baseball card collector problem is as follows: Given packets P1, P2, . . . , PM,

Question:

The baseball card collector problem is as follows: Given packets P1, P2, . . . , PM, each of which contains a subset of the year's baseball cards, and an integer K, is it possible to collect all the baseball cards by choosing ≤ K packets? Show that the baseball card collector problem is NP-complete.