Seatsorter
An online bin-packing problem I met first as a host, not a student.
Why I built it
Seating a restaurant is a scheduling problem wearing an apron. A party of five arrives, you have a four-top and a six-top open, and the six-top is the only table that fits the eight-person reservation due in twenty minutes.
You make that call in about three seconds, and you make it wrong often enough to notice. So I wrote down what I was actually doing and turned it into a solver.
How it works
Requests arrive one at a time and have to be placed without knowing what's coming next. That's the online version of the problem, which means no perfect answer, just better and worse heuristics.