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Topic: Endgame Puzzle 1 (Read 542 times) |
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aaaa
Forum Guru
Arimaa player #958
Posts: 768
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Re: Endgame Puzzle 1
« Reply #1 on: Jul 27th, 2008, 7:03am » |
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Here's my attempt:
2b ra5e rb5s rb4e rc4e
3w Ca1e Cb1e Cc1e Rd2e
3b rd4e re4e rf4e
4w Cd1e Ce1e Cf1n Cf2e
4b rg4w rf4w re4w rd4w and wins
[EDIT]
Alternate defense:
3w Ca1e Cb1e Cc1e Cd1e
3b rd4w rc4w
4w Ce1w Cd1w Cc1n Cc2w
4b rb4e rc4e rd4e re4e and wins
[/EDIT]
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| « Last Edit: Jul 27th, 2008, 7:44am by aaaa » |
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Fritzlein
Forum Guru
Arimaa player #706
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Posts: 5928
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Re: Endgame Puzzle 1
« Reply #2 on: Jul 27th, 2008, 7:48am » |
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Elmo and I agree with your solution. However, there is an interesting footnote. If Gold deviates with
2b ra5e rb5s rb4e rc4e
3w Ca1e Cb1e Cc1e Cd1e
then Silver can make a winning position symmetrical to the one you made with
3b rd4w rc4w
winning in the same total number of moves. When Elmo and I were satisfied with our solution, we checked it with Bomb. The position is small enough that Bomb can find a forced win in four in less than a second. However, Bomb considers the initial position a forced loss for Silver!
We dug a bit deeper and discovered why Bomb gets the wrong answer. When it is building its search tree, it allows a pass only on the fourth step, i.e. it can only make three-step or four-step moves. Why didn't Fotland allow two-step moves? Well, my guess is that he supposed one could make a four-step move into a two-step move by burning two of the steps with, say, a forward-and-back shuffle, so allowing four-step moves effectively allows two-step moves. However, in this position, Gold has no piece to shuffle except the rabbit. Once it starts stepping west on 3b, it can't step back east without hitting the hash table, which I am guessing effectively disallows that step.
This is just a warning to anyone out there who is composing "Goal in X" puzzles with the help of Bomb. In the endgame it is often necessary and correct to lose a step or two, and Bomb apparently can't do that quite correctly.
[EDIT]
I see your edit anticipated the alternate defense while I was typing my reply 
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| « Last Edit: Jul 27th, 2008, 8:29am by Fritzlein » |
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