Monday, April 26, 2004

Is Disney World NP-complete?

The Unofficial Guide to Walt Disney World 2004 gives a lesson on complexity by describing the optimal tour of the Magic Kingdom as a traveling salesman problem. Some excerpts:
As we add more attractions to our list, the number of possible touring plans grows rapidly...The 21 attractions in the Magic Kingdom One-Day Touring Plan for Adults as a staggering 51,090,942,171,709,440,000 possible touring plans...roughly six times more than the estimated number of grains of sand in the whole world...Fortunately, scientists have been hard at work on similar problems for many years..finding good ways to visit many places with minimum effort is such a common problem that it has its own nickname: the traveling salesman problem.
The book goes on to describe the computer program they use to approximate the optimal tour. Read more here (which I found by searching within the book for "traveling salesman" on the Amazon site). You'll need to be a registered user of to read it.