When reading the story, I thought, "well of course that's the solution ...", but then couldn't recall ever learning it. I'm grateful that someone shared the na

When reading the story, I thought, "well of course that's the solution ...", but then couldn't recall ever learning it. I'm grateful that someone shared the name, as Wikipedia's explanation is surprisingly clear: https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_Tortoise_and_Hare https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_Tortoi...