The Doomsday Rule
John Horton Conway has taught me a lot of things over the years: all about Life, my first computational obsession; how to turn numbers into games; and (most recently) that subatomic particles have free will.
The one lesson that I apply most frequently these days, however, is the Doomsday Rule. Here are S.W. Graham’s excellent notes on the algorithm, with bonus approaches to computing Easter and Rosh Hashana as well.
