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Hide and destroy (Posted on 2006-02-15) Difficulty: 3 of 5
You must randomly place a destroyer (a 1x2 sized ship) on a 5x5 grid such that if I searched in any single square, my probability of finding the destroyer there is exactly 2/25. Is such a probability distribution possible? You cannot simply choose randomly one of the 40 possible positions of a destroyer because corners would have a 1/20 chance to contain the destroyer, while the center would have 1/10 chance.

Generalize to a 1xN sized ship in a MxM grid. When is it possible to place the ship with an even probability distribution in each square?

See The Solution Submitted by Tristan    
Rating: 3.4000 (5 votes)

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re: Clarification, if you're lost | Comment 8 of 13 |
(In reply to Clarification, if you're lost by Tristan)

Anything wrong with the "Try this" solution?  It works when M is a multiple of N, so maybe the 5x5 with the 1x2 can't be done?


  Posted by bernie on 2006-02-16 13:46:31
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