I've written a political quiz based on data from the public whip. They group politicians' votes by policy; each vote can belong to many policies. There are too many policies for me to ask a question for each one, and anyway some are duplicates and some policies' votes are subsets of other policies. In the past, I've manually chosen a subset of policies to use in my quiz try to maximise the number of votes included without double-counting any, but I'm worried that that may introduce my biases into what is supposed to be as neutral as possible a quiz. So I'd like to find the set of policies which maximises the number of votes included without counting any of them twice.
Is there a known algorithm I could use to do this? I've seen similar questions elsewhere on this site but they generally seem to involve sets of intervals or geometric shapes.