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 Xyzzy 2014-07-16 06:17

July 2014

[url]http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/challenges/July2014.html[/url]

Whew, where to start?

:max:

 axn 2014-07-16 06:29

[QUOTE=Xyzzy;378206][url]http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/challenges/July2014.html[/url]

Whew, where to start?

:max:[/QUOTE]

Start by noticing that all the numbers are consecutive Fibonacci numbers

 retina 2014-07-16 07:39

Perhaps I missed something in the description but it seems that the first player can easily win by [spoiler]simply taking all of the pebbles on the first move leaving none the the second player[/spoiler].

Edit: Oops, I certainly did miss something. The shape is supposed to be three dimensional.

 Brian-E 2014-07-16 07:54

[QUOTE=retina;378217]Edit: Oops, I certainly did miss something.[/QUOTE]
Hardly surprising, the problem is not very well described. The notation for the example moves seems a little odd too: clearly the six numbers in a move are numbers of pebbles to be taken from each edge of the tetrahedron, but nowhere does the writer define in which order the edges are considered.

I suppose the problem is a variation of the game of [URL="http://en.wikipedia.org/wiki/Nim"]Nim[/URL].

 axn 2014-07-16 08:17

[QUOTE=Brian-E;378218]but nowhere does the writer define in which order the edges are considered.[/QUOTE]

The edges are ordered based on the initial values (1,2,3,5,8,13). The examples clarify that.

 science_man_88 2014-07-16 23:33

so they want all the possible lines to winning ?

 Xyzzy 2014-11-02 19:05

[url]http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/solutions/July2014.html[/url]

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