Tim Daly, Jr. <firstname.lastname@example.org> wrote:
| "Paul F. Dietz" <email@example.com> writes:
| > (idea: detect circularity using the standard two pointer trick
| > and use MOD to reduce n to a manageable size.)
| Could someone please clue me in on the "standard two pointer trick"?
Do a web search for:
tortoise hare circular
or perhaps better:
tortoise hare "circular list"
Also see CLHS "Function LIST-LENGTH". As shown there, a common approach
is to have the hare move at twice the speed of the tortoise, but many
other winning strategies are possible [iff your termination tests are
correct!]. E.g., make the tortoise move at half the speed of the hare.
[It is useful to ask why/how this might be different than the previous,
and whether or not one might be "better" than the other in some sense.]
Rob Warnock, PP-ASEL-IA <firstname.lastname@example.org>
627 26th Avenue <URL:http://rpw3.org/>
San Mateo, CA 94403 (650)572-2607