N = 1 ( A -> B)
当 n > 2 and n = 奇数时,N = 2 ( A -> B, B -> A)。
当 n > 2 and n = 偶数时,N = 3 ( A -> B, 排除一根,n 成奇数, B -> A, A -> B )。
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没太理解- some good thought but seems you are incorrect
-guest007-
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02/13/2010 postreply
18:29:55