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发帖数: 921 | 1 【 以下文字转载自 BrainTeaser 讨论区 】
发信人: orion (M42), 信区: BrainTeaser
标 题: 出个permutation的问题
发信站: BBS 未名空间站 (Thu Mar 20 11:33:26 2008), 转信
If the girlfriends of 3 couples are seated in fixed position around a table,
there is only one possible way to seat their boyfriends so that men and
women alternate and no boyfriend is next to his girlfriend. With 4 couples,
there are two possible arrangements.
How many possible arrangements are there with 5, 6, and 10 couples? |
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