I'm trying to come up with a reduction for a problem whose description is more or less identical to the first problem given here.
Here's a condensed version of the problem:
You're given a collection of refrigerator magnet letters that may contain duplicates. You have a limited vocabulary of words made of combinations of those letters (again, a word may contain the same letter twice). Can you choose words from the vocabulary to build with the magnets such that all of the magnets are used and each magnet is used in only one word?
It's suspiciously similar to the set cover problem, so I've been trying to come up with a way to convert (in polynomial time) a collection of symbols that potentially contains duplicates into a set. This would allow the collection of symbols to be used as U and the child's vocabulary to be used as S for set cover.
I've had no luck so far, so a hint or even a suggestion for a more appropriate NP-complete problem to reduce to would be greatly appreciated.