m people and n rooms: C(m+n-1,m), instead of C(m+n-1,n).

来源: 于 2010-06-17 10:00:40 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

C(m+n-1,m) = C(m+n-1,n-1)