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Re:判断C(n,m)的奇偶性

Posted by endkiller at 2011-02-16 20:52:46 on Problem 1430
In Reply To:判断C(n,m)的奇偶性 Posted by:Ly86 at 2010-09-10 16:14:18

> RT
> 当然
> 要通过一定的变换
> 把求stirling number 的 n,m变换成组合数的n,m
当m为奇数时 n，m变为 n-(m+1)/2,(m-1)/2 然后答案与C(n,m)奇偶性相同
当m为偶数时 答案与n-1，m-1相同，然后按奇数的方法算

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