Monday, December 28, 2009

I feel like I'm approaching this stupidly, so if you have any ideas, I would be grateful. Hints that trivialize the problem are not welcome.

The integers 1 to n listed in order. A swap is a switching of any two elements in the list. Prove that any sequence of swaps that takes the original list to itself contains an even number of swaps.
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2 comments:

  1. WaitingForGodotDecember 28, 2009 at 11:03 PM

    I don't really know how to rigorously prove that, but intuitively it seems pretty obvious. I have an idea, but I'm not entirely sure that it won't trivialize the problem sso I'll hold off on saying it.

    ReplyDelete
  2. Jessica LiuJanuary 21, 2010 at 1:58 PM

    prove it doesn't!
    also, SEND ME BATTLECODEEEEE omg

    ReplyDelete

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