Using your Head is Permitted

October 2013 riddle

UPDATE (6 October): This month, an asterisk will be added next to the name of any solver whose solution is valid for any NxN board with even N.

I had lots of fun with last month's riddle, and so did Yaron Gvili, and we both thought it would be a good idea to have a follow-up riddle, which Yaron came up with.

This month's riddle: find a maximal length closed king's tour on the 8x8 chessboard.

This is essentially the same riddle as last month's riddle, but using a chess king rather than a chess rook.

Some notes:

  1. Use for this riddle the same format for the reply as in last month's riddle. The format is described there.
  2. This time, you are required to prove maximality. (Many readers saw last month's "result only" as a green light to write greedy searching software. That wasn't the intention.)
  3. Though it makes no difference to the actual solution, to keep the numbers simple use Manhattan distance as the distance metric for the king's moves, rather than Euclidean distance.

List of solvers:

Lorenz Reichel (*) (6 October 07:26)
Yang Ling (*) (6 October 12:48)
Joseph DeVincentis (8 October 05:56)
Radu-Alexandru Todor (9 October 08:56)
Guangda Huzhang (*) (20 October 04:18)
Lorenzo Gianferrari Pini (23 October 04:14)
Daniel Bitin (28 October 03:29)
Todd Will (28 October 05:09)
Andreas Stiller (31 October 06:28)

Elegant and original solutions can be submitted to the puzzlemaster at Names of solvers will be posted on this page. Notify if you don't want your name to be mentioned.

The solution will be published at the end of the month.


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