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February 2023 - Challenge
In the eight queens problem, eight queens must be placed on a chessboard in such a way that no pair of queens is currently threatening one another. One possible solution to the eight queens problem is this:
With apologies to standard chess notation, we can describe the locations of the queens and kings on this board using the following two lists of coordinates:
[(0, 2), (1, 5), (2, 3), (3, 1), (4, 7), (5, 4), (6, 6), (7, 0)]
[(1, 7), (3, 0), (7, 1), (7, 3)]
For , an
board and the following queen configuration:
[(0, 1), (1, 9), (2, 7), (3, 5), (4, 3), (5, 12), (6, 10), (7, 13), (8, 11), (9, 6), (10, 4), (11, 2), (12, 0), (13, 8)]
Is it possible to find arrangement of kings. One such arrangement is
[(0, 0), (1, 10), (2, 0), (4, 0), (4, 2), (9, 2), (9, 9), (11, 0), (11, 7), (11, 11), (13, 5), (13, 9), (13, 11), (13, 13)]
There are 41 possible arrangements of kings in total.
Your goal: Find a placement of queens on an
board such that no pair of queens threatens each other, and the number of different ways to place
kings on the safe squares without any pair of kings currently threatening one another is 48.
Supply your answer in a list of the queen positions, as in the above example.
A bonus "*" will be given for finding a placement of queens on an
board such that no pair of queens is currently threatening one another, and there is no way to place
kings on the safe squares without any pair of kings threatening each other, for
.
We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!
We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.
If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com
Challenge:
02/02/2023 @ 10:00 AM EST
Solution:
05/03/2023 @ 12:00 PM EST
List Updated:
22/03/2023 @ 11:30 AM EST
People who answered correctly:
*Lorenz Reichel(2/2/2023 3:06 PM IDT)
*Paul Revenant(2/2/2023 4:54 PM IDT)
*Amos Guler(3/2/2023 3:10 AM IDT)
*Bertram Felgenhauer(3/2/2023 6:03 AM IDT)
*Gary M. Gerken(3/2/2023 7:12 AM IDT)
*Alper Halbutogullari(3/2/2023 8:46 AM IDT)
*Reiner Martin(3/2/2023 1:59 PM IDT)
*Lorenzo Gianferrari Pini(3/2/2023 4:33 PM IDT)
Vamsi Krishna Talupula(3/2/2023 7:28 PM IDT)
Giorgos Kalogeropoulos(3/2/2023 8:29 PM IDT)
*Daniel Bitin(3/2/2023 11:34 PM IDT)
*Dieter Beckerle(4/2/2023 3:45 PM IDT)
*Daniel Chong Jyh Tar(4/2/2023 5:24 PM IDT)
Richard Gosiorovsky(4/2/2023 6:09 PM IDT)
*Todd Will(4/2/2023 6:47 PM IDT)
David Greer(4/2/2023 8:27 PM IDT)
V.Barbera(5/2/2023 1:08 AM IDT)
*Stefan Berger(5/2/2023 3:42 PM IDT)
*Hakan Summakoğlu(5/2/2023 7:59 PM IDT)
*Tim Walters(6/2/2023 2:09 AM IDT)
*David F.H. Dunkley(6/2/2023 2:42 AM IDT)
*Harald Bögeholz(6/2/2023 10:27 AM IDT)
Graham Hemsley(6/2/2023 11:22 AM IDT)
Dan Dima(6/2/2023 2:54 PM IDT)
*Guillaume Escamocher(6/2/2023 5:08 PM IDT)
*Latchezar Christov(7/2/2023 6:32 PM IDT)
*Bert Dobbelaere(7/2/2023 9:11 PM IDT)
*Vladimir Volevich(8/2/2023 2:33 PM IDT)
*K S(8/2/2023 11:23 PM IDT)
*Martin Thorne(9/2/2023 7:30 PM IDT)
*Andreas Knüpfer(9/2/2023 9:19 PM IDT)
*Sanandan Swaminathan(11/2/2023 11:24 AM IDT)
Alex Fleischer(11/2/2023 3:01 PM IDT)
*John Tromp(12/2/2023 12:56 AM IDT)
Clive Tong(13/2/2023 10:32 AM IDT)
*Thomas Ilsche(13/2/2023 4:56 PM IDT)
*Stéphane Higueret(13/2/2023 10:55 PM IDT)
*Chris Shannon(14/2/2023 8:34 PM IDT)
*Phil Proudman(15/2/2023 5:10 PM IDT)
Sri Mallikarjun(15/2/2023 7:28 PM IDT)
*Mario Bielert(15/2/2023 9:38 PM IDT)
*Marco Bellocchi(16/2/2023 12:02 AM IDT)
Michael Liepelt(17/2/2023 8:20 AM IDT)
Ranjit Eswaran(18/2/2023 4:12 PM IDT)
*Phong Kah Ho(18/2/2023 9:09 PM IDT)
Prashant Wankhede(20/2/2023 3:36 AM IDT)
*Jean-Matthieu Schertzer(20/2/2023 12:47 PM IDT)
Jesús V(20/2/2023 8:25 PM IDT)
*Li Li(21/2/2023 7:28 PM IDT)
*Evert van Dijken(22/2/2023 12:58 PM IDT)
*Alexander Marschoun(23/2/2023 10:23 PM IDT)
*Nyles Heise(25/2/2023 6:12 AM IDT)
*Andreas Puccio(27/2/2023 12:42 PM IDT)
*Motty Porat(28/2/2023 7:33 PM IDT)
Jet Semrick(1/3/2023 12:53 AM IDT)
*Radu-Alexandru Todor(1/3/2023 1:09 AM IDT)
*Stephen Herbert Jr(1/3/2023 9:05 PM IDT)
John Goh(4/3/2023 5:15 PM IDT)
Virginia Ardévol Martínez(5/3/2023 11:14 PM IDT)
Elias Werner(13/3/2023 6:32 PM IDT)