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[组合] z,绝对值差某些是1

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realnumber Posted 2014-4-15 14:36 |Read mode
Last edited by realnumber 2014-4-15 14:48 QQ图片20140415143440.jpg
答案B

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 Author| realnumber Posted 2014-4-15 15:08
同事韩的解答:
先前3位排好,可以是123,234,345,456,某个排列,再第四,五位,最后一个任意。

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 Author| realnumber Posted 2014-4-15 18:32
同事王的解答:

54321与6共6个,4321与56共10个,321与456共10个,21与3456共5个,1与23456就1个,总共32个
\[C_6^1+C_5^2+C_5^3+C_5^4+C_5^5=32\]

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 Author| realnumber Posted 2014-4-15 19:47
徐:只有12两个数的话 答案是2
3个数的话,答案是4
4个是8
5个是16

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 Author| realnumber Posted 2014-4-15 19:57
王:
[ ]( )( )( )( )( ),每个圆括弧内都可以选+或-,总共是2^5=32种,每种填法对应一种符合要求的排列
朱:[]?什么意思,还有+,-对应着数字增加1减小1?
王:[ ](+)(+)(-)(+)(-),则对应345261
朱:+-++-意思是342561对吗?
王:恩

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