回复：回复：让人烦恼的礼金卡问题

来源: 于 2009-01-06 01:54:19 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

The optimal solution gets you 1000 * r, where r is the value such that 0
r*(1-r)/(1-0.81*r*r)