pub fn hitting_set(universe: usize, sets: &[Vec<usize>]) -> Vec<usize>Expand description
Greedy hitting set: find a small set H ⊆ {0..universe-1} such that every input set contains at least one element of H.
Equivalent to set cover on the dual hypergraph. Greedily picks the element that “hits” the most unhit sets.
Returns the hitting set as a sorted list of element indices.