Where to advertise

A consumer brand wants to reach 80% of US adult women aged 25–44 at least once. Each ad placement (a podcast, a primetime slot, a billboard, a TikTok creator) reaches a set of that audience, with overlap between channels. Picking the cheapest combination of placements that covers the audience is set cover. The same template runs in vaccine campaigns (each clinic location covers a population catchment area), in disaster relief (each warehouse covers a service radius), in software testing (each test case covers a set of branches — minimum-cover-by-tests is the basis of test-suite reduction tools), and in genome assembly (each read covers a stretch of the genome). The greedy heuristic is the working horse; nobody waits for the IP solver in the marketing meeting.